summaryrefslogtreecommitdiff
path: root/Lib/datetime.py
blob: a964b202e3c7a9856c46014fd98fb5f11d9b93d6 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
"""Concrete date/time and related types.

See http://www.iana.org/time-zones/repository/tz-link.html for
time zone and DST data sources.
"""

import time as _time
import math as _math
import sys

def _cmp(x, y):
    return 0 if x == y else 1 if x > y else -1

MINYEAR = 1
MAXYEAR = 9999
_MAXORDINAL = 3652059  # date.max.toordinal()

# Utility functions, adapted from Python's Demo/classes/Dates.py, which
# also assumes the current Gregorian calendar indefinitely extended in
# both directions.  Difference:  Dates.py calls January 1 of year 0 day
# number 1.  The code here calls January 1 of year 1 day number 1.  This is
# to match the definition of the "proleptic Gregorian" calendar in Dershowitz
# and Reingold's "Calendrical Calculations", where it's the base calendar
# for all computations.  See the book for algorithms for converting between
# proleptic Gregorian ordinals and many other calendar systems.

# -1 is a placeholder for indexing purposes.
_DAYS_IN_MONTH = [-1, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]

_DAYS_BEFORE_MONTH = [-1]  # -1 is a placeholder for indexing purposes.
dbm = 0
for dim in _DAYS_IN_MONTH[1:]:
    _DAYS_BEFORE_MONTH.append(dbm)
    dbm += dim
del dbm, dim

def _is_leap(year):
    "year -> 1 if leap year, else 0."
    return year % 4 == 0 and (year % 100 != 0 or year % 400 == 0)

def _days_before_year(year):
    "year -> number of days before January 1st of year."
    y = year - 1
    return y*365 + y//4 - y//100 + y//400

def _days_in_month(year, month):
    "year, month -> number of days in that month in that year."
    assert 1 <= month <= 12, month
    if month == 2 and _is_leap(year):
        return 29
    return _DAYS_IN_MONTH[month]

def _days_before_month(year, month):
    "year, month -> number of days in year preceding first day of month."
    assert 1 <= month <= 12, 'month must be in 1..12'
    return _DAYS_BEFORE_MONTH[month] + (month > 2 and _is_leap(year))

def _ymd2ord(year, month, day):
    "year, month, day -> ordinal, considering 01-Jan-0001 as day 1."
    assert 1 <= month <= 12, 'month must be in 1..12'
    dim = _days_in_month(year, month)
    assert 1 <= day <= dim, ('day must be in 1..%d' % dim)
    return (_days_before_year(year) +
            _days_before_month(year, month) +
            day)

_DI400Y = _days_before_year(401)    # number of days in 400 years
_DI100Y = _days_before_year(101)    #    "    "   "   " 100   "
_DI4Y   = _days_before_year(5)      #    "    "   "   "   4   "

# A 4-year cycle has an extra leap day over what we'd get from pasting
# together 4 single years.
assert _DI4Y == 4 * 365 + 1

# Similarly, a 400-year cycle has an extra leap day over what we'd get from
# pasting together 4 100-year cycles.
assert _DI400Y == 4 * _DI100Y + 1

# OTOH, a 100-year cycle has one fewer leap day than we'd get from
# pasting together 25 4-year cycles.
assert _DI100Y == 25 * _DI4Y - 1

def _ord2ymd(n):
    "ordinal -> (year, month, day), considering 01-Jan-0001 as day 1."

    # n is a 1-based index, starting at 1-Jan-1.  The pattern of leap years
    # repeats exactly every 400 years.  The basic strategy is to find the
    # closest 400-year boundary at or before n, then work with the offset
    # from that boundary to n.  Life is much clearer if we subtract 1 from
    # n first -- then the values of n at 400-year boundaries are exactly
    # those divisible by _DI400Y:
    #
    #     D  M   Y            n              n-1
    #     -- --- ----        ----------     ----------------
    #     31 Dec -400        -_DI400Y       -_DI400Y -1
    #      1 Jan -399         -_DI400Y +1   -_DI400Y      400-year boundary
    #     ...
    #     30 Dec  000        -1             -2
    #     31 Dec  000         0             -1
    #      1 Jan  001         1              0            400-year boundary
    #      2 Jan  001         2              1
    #      3 Jan  001         3              2
    #     ...
    #     31 Dec  400         _DI400Y        _DI400Y -1
    #      1 Jan  401         _DI400Y +1     _DI400Y      400-year boundary
    n -= 1
    n400, n = divmod(n, _DI400Y)
    year = n400 * 400 + 1   # ..., -399, 1, 401, ...

    # Now n is the (non-negative) offset, in days, from January 1 of year, to
    # the desired date.  Now compute how many 100-year cycles precede n.
    # Note that it's possible for n100 to equal 4!  In that case 4 full
    # 100-year cycles precede the desired day, which implies the desired
    # day is December 31 at the end of a 400-year cycle.
    n100, n = divmod(n, _DI100Y)

    # Now compute how many 4-year cycles precede it.
    n4, n = divmod(n, _DI4Y)

    # And now how many single years.  Again n1 can be 4, and again meaning
    # that the desired day is December 31 at the end of the 4-year cycle.
    n1, n = divmod(n, 365)

    year += n100 * 100 + n4 * 4 + n1
    if n1 == 4 or n100 == 4:
        assert n == 0
        return year-1, 12, 31

    # Now the year is correct, and n is the offset from January 1.  We find
    # the month via an estimate that's either exact or one too large.
    leapyear = n1 == 3 and (n4 != 24 or n100 == 3)
    assert leapyear == _is_leap(year)
    month = (n + 50) >> 5
    preceding = _DAYS_BEFORE_MONTH[month] + (month > 2 and leapyear)
    if preceding > n:  # estimate is too large
        month -= 1
        preceding -= _DAYS_IN_MONTH[month] + (month == 2 and leapyear)
    n -= preceding
    assert 0 <= n < _days_in_month(year, month)

    # Now the year and month are correct, and n is the offset from the
    # start of that month:  we're done!
    return year, month, n+1

# Month and day names.  For localized versions, see the calendar module.
_MONTHNAMES = [None, "Jan", "Feb", "Mar", "Apr", "May", "Jun",
                     "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"]
_DAYNAMES = [None, "Mon", "Tue", "Wed", "Thu", "Fri", "Sat", "Sun"]


def _build_struct_time(y, m, d, hh, mm, ss, dstflag):
    wday = (_ymd2ord(y, m, d) + 6) % 7
    dnum = _days_before_month(y, m) + d
    return _time.struct_time((y, m, d, hh, mm, ss, wday, dnum, dstflag))

def _format_time(hh, mm, ss, us, timespec='auto'):
    specs = {
        'hours': '{:02d}',
        'minutes': '{:02d}:{:02d}',
        'seconds': '{:02d}:{:02d}:{:02d}',
        'milliseconds': '{:02d}:{:02d}:{:02d}.{:03d}',
        'microseconds': '{:02d}:{:02d}:{:02d}.{:06d}'
    }

    if timespec == 'auto':
        # Skip trailing microseconds when us==0.
        timespec = 'microseconds' if us else 'seconds'
    elif timespec == 'milliseconds':
        us //= 1000
    try:
        fmt = specs[timespec]
    except KeyError:
        raise ValueError('Unknown timespec value')
    else:
        return fmt.format(hh, mm, ss, us)

def _format_offset(off):
    s = ''
    if off is not None:
        if off.days < 0:
            sign = "-"
            off = -off
        else:
            sign = "+"
        hh, mm = divmod(off, timedelta(hours=1))
        mm, ss = divmod(mm, timedelta(minutes=1))
        s += "%s%02d:%02d" % (sign, hh, mm)
        if ss or ss.microseconds:
            s += ":%02d" % ss.seconds

            if ss.microseconds:
                s += '.%06d' % ss.microseconds
    return s

# Correctly substitute for %z and %Z escapes in strftime formats.
def _wrap_strftime(object, format, timetuple):
    # Don't call utcoffset() or tzname() unless actually needed.
    freplace = None  # the string to use for %f
    zreplace = None  # the string to use for %z
    Zreplace = None  # the string to use for %Z

    # Scan format for %z and %Z escapes, replacing as needed.
    newformat = []
    push = newformat.append
    i, n = 0, len(format)
    while i < n:
        ch = format[i]
        i += 1
        if ch == '%':
            if i < n:
                ch = format[i]
                i += 1
                if ch == 'f':
                    if freplace is None:
                        freplace = '%06d' % getattr(object,
                                                    'microsecond', 0)
                    newformat.append(freplace)
                elif ch == 'z':
                    if zreplace is None:
                        zreplace = ""
                        if hasattr(object, "utcoffset"):
                            offset = object.utcoffset()
                            if offset is not None:
                                sign = '+'
                                if offset.days < 0:
                                    offset = -offset
                                    sign = '-'
                                h, rest = divmod(offset, timedelta(hours=1))
                                m, rest = divmod(rest, timedelta(minutes=1))
                                s = rest.seconds
                                u = offset.microseconds
                                if u:
                                    zreplace = '%c%02d%02d%02d.%06d' % (sign, h, m, s, u)
                                elif s:
                                    zreplace = '%c%02d%02d%02d' % (sign, h, m, s)
                                else:
                                    zreplace = '%c%02d%02d' % (sign, h, m)
                    assert '%' not in zreplace
                    newformat.append(zreplace)
                elif ch == 'Z':
                    if Zreplace is None:
                        Zreplace = ""
                        if hasattr(object, "tzname"):
                            s = object.tzname()
                            if s is not None:
                                # strftime is going to have at this: escape %
                                Zreplace = s.replace('%', '%%')
                    newformat.append(Zreplace)
                else:
                    push('%')
                    push(ch)
            else:
                push('%')
        else:
            push(ch)
    newformat = "".join(newformat)
    return _time.strftime(newformat, timetuple)

# Helpers for parsing the result of isoformat()
def _parse_isoformat_date(dtstr):
    # It is assumed that this function will only be called with a
    # string of length exactly 10, and (though this is not used) ASCII-only
    year = int(dtstr[0:4])
    if dtstr[4] != '-':
        raise ValueError('Invalid date separator: %s' % dtstr[4])

    month = int(dtstr[5:7])

    if dtstr[7] != '-':
        raise ValueError('Invalid date separator')

    day = int(dtstr[8:10])

    return [year, month, day]

def _parse_hh_mm_ss_ff(tstr):
    # Parses things of the form HH[:MM[:SS[.fff[fff]]]]
    len_str = len(tstr)

    time_comps = [0, 0, 0, 0]
    pos = 0
    for comp in range(0, 3):
        if (len_str - pos) < 2:
            raise ValueError('Incomplete time component')

        time_comps[comp] = int(tstr[pos:pos+2])

        pos += 2
        next_char = tstr[pos:pos+1]

        if not next_char or comp >= 2:
            break

        if next_char != ':':
            raise ValueError('Invalid time separator: %c' % next_char)

        pos += 1

    if pos < len_str:
        if tstr[pos] != '.':
            raise ValueError('Invalid microsecond component')
        else:
            pos += 1

            len_remainder = len_str - pos
            if len_remainder not in (3, 6):
                raise ValueError('Invalid microsecond component')

            time_comps[3] = int(tstr[pos:])
            if len_remainder == 3:
                time_comps[3] *= 1000

    return time_comps

def _parse_isoformat_time(tstr):
    # Format supported is HH[:MM[:SS[.fff[fff]]]][+HH:MM[:SS[.ffffff]]]
    len_str = len(tstr)
    if len_str < 2:
        raise ValueError('Isoformat time too short')

    # This is equivalent to re.search('[+-]', tstr), but faster
    tz_pos = (tstr.find('-') + 1 or tstr.find('+') + 1)
    timestr = tstr[:tz_pos-1] if tz_pos > 0 else tstr

    time_comps = _parse_hh_mm_ss_ff(timestr)

    tzi = None
    if tz_pos > 0:
        tzstr = tstr[tz_pos:]

        # Valid time zone strings are:
        # HH:MM               len: 5
        # HH:MM:SS            len: 8
        # HH:MM:SS.ffffff     len: 15

        if len(tzstr) not in (5, 8, 15):
            raise ValueError('Malformed time zone string')

        tz_comps = _parse_hh_mm_ss_ff(tzstr)
        if all(x == 0 for x in tz_comps):
            tzi = timezone.utc
        else:
            tzsign = -1 if tstr[tz_pos - 1] == '-' else 1

            td = timedelta(hours=tz_comps[0], minutes=tz_comps[1],
                           seconds=tz_comps[2], microseconds=tz_comps[3])

            tzi = timezone(tzsign * td)

    time_comps.append(tzi)

    return time_comps


# Just raise TypeError if the arg isn't None or a string.
def _check_tzname(name):
    if name is not None and not isinstance(name, str):
        raise TypeError("tzinfo.tzname() must return None or string, "
                        "not '%s'" % type(name))

# name is the offset-producing method, "utcoffset" or "dst".
# offset is what it returned.
# If offset isn't None or timedelta, raises TypeError.
# If offset is None, returns None.
# Else offset is checked for being in range.
# If it is, its integer value is returned.  Else ValueError is raised.
def _check_utc_offset(name, offset):
    assert name in ("utcoffset", "dst")
    if offset is None:
        return
    if not isinstance(offset, timedelta):
        raise TypeError("tzinfo.%s() must return None "
                        "or timedelta, not '%s'" % (name, type(offset)))
    if not -timedelta(1) < offset < timedelta(1):
        raise ValueError("%s()=%s, must be strictly between "
                         "-timedelta(hours=24) and timedelta(hours=24)" %
                         (name, offset))

def _check_int_field(value):
    if isinstance(value, int):
        return value
    if not isinstance(value, float):
        try:
            value = value.__int__()
        except AttributeError:
            pass
        else:
            if isinstance(value, int):
                return value
            raise TypeError('__int__ returned non-int (type %s)' %
                            type(value).__name__)
        raise TypeError('an integer is required (got type %s)' %
                        type(value).__name__)
    raise TypeError('integer argument expected, got float')

def _check_date_fields(year, month, day):
    year = _check_int_field(year)
    month = _check_int_field(month)
    day = _check_int_field(day)
    if not MINYEAR <= year <= MAXYEAR:
        raise ValueError('year must be in %d..%d' % (MINYEAR, MAXYEAR), year)
    if not 1 <= month <= 12:
        raise ValueError('month must be in 1..12', month)
    dim = _days_in_month(year, month)
    if not 1 <= day <= dim:
        raise ValueError('day must be in 1..%d' % dim, day)
    return year, month, day

def _check_time_fields(hour, minute, second, microsecond, fold):
    hour = _check_int_field(hour)
    minute = _check_int_field(minute)
    second = _check_int_field(second)
    microsecond = _check_int_field(microsecond)
    if not 0 <= hour <= 23:
        raise ValueError('hour must be in 0..23', hour)
    if not 0 <= minute <= 59:
        raise ValueError('minute must be in 0..59', minute)
    if not 0 <= second <= 59:
        raise ValueError('second must be in 0..59', second)
    if not 0 <= microsecond <= 999999:
        raise ValueError('microsecond must be in 0..999999', microsecond)
    if fold not in (0, 1):
        raise ValueError('fold must be either 0 or 1', fold)
    return hour, minute, second, microsecond, fold

def _check_tzinfo_arg(tz):
    if tz is not None and not isinstance(tz, tzinfo):
        raise TypeError("tzinfo argument must be None or of a tzinfo subclass")

def _cmperror(x, y):
    raise TypeError("can't compare '%s' to '%s'" % (
                    type(x).__name__, type(y).__name__))

def _divide_and_round(a, b):
    """divide a by b and round result to the nearest integer

    When the ratio is exactly half-way between two integers,
    the even integer is returned.
    """
    # Based on the reference implementation for divmod_near
    # in Objects/longobject.c.
    q, r = divmod(a, b)
    # round up if either r / b > 0.5, or r / b == 0.5 and q is odd.
    # The expression r / b > 0.5 is equivalent to 2 * r > b if b is
    # positive, 2 * r < b if b negative.
    r *= 2
    greater_than_half = r > b if b > 0 else r < b
    if greater_than_half or r == b and q % 2 == 1:
        q += 1

    return q


class timedelta:
    """Represent the difference between two datetime objects.

    Supported operators:

    - add, subtract timedelta
    - unary plus, minus, abs
    - compare to timedelta
    - multiply, divide by int

    In addition, datetime supports subtraction of two datetime objects
    returning a timedelta, and addition or subtraction of a datetime
    and a timedelta giving a datetime.

    Representation: (days, seconds, microseconds).  Why?  Because I
    felt like it.
    """
    __slots__ = '_days', '_seconds', '_microseconds', '_hashcode'

    def __new__(cls, days=0, seconds=0, microseconds=0,
                milliseconds=0, minutes=0, hours=0, weeks=0):
        # Doing this efficiently and accurately in C is going to be difficult
        # and error-prone, due to ubiquitous overflow possibilities, and that
        # C double doesn't have enough bits of precision to represent
        # microseconds over 10K years faithfully.  The code here tries to make
        # explicit where go-fast assumptions can be relied on, in order to
        # guide the C implementation; it's way more convoluted than speed-
        # ignoring auto-overflow-to-long idiomatic Python could be.

        # XXX Check that all inputs are ints or floats.

        # Final values, all integer.
        # s and us fit in 32-bit signed ints; d isn't bounded.
        d = s = us = 0

        # Normalize everything to days, seconds, microseconds.
        days += weeks*7
        seconds += minutes*60 + hours*3600
        microseconds += milliseconds*1000

        # Get rid of all fractions, and normalize s and us.
        # Take a deep breath <wink>.
        if isinstance(days, float):
            dayfrac, days = _math.modf(days)
            daysecondsfrac, daysecondswhole = _math.modf(dayfrac * (24.*3600.))
            assert daysecondswhole == int(daysecondswhole)  # can't overflow
            s = int(daysecondswhole)
            assert days == int(days)
            d = int(days)
        else:
            daysecondsfrac = 0.0
            d = days
        assert isinstance(daysecondsfrac, float)
        assert abs(daysecondsfrac) <= 1.0
        assert isinstance(d, int)
        assert abs(s) <= 24 * 3600
        # days isn't referenced again before redefinition

        if isinstance(seconds, float):
            secondsfrac, seconds = _math.modf(seconds)
            assert seconds == int(seconds)
            seconds = int(seconds)
            secondsfrac += daysecondsfrac
            assert abs(secondsfrac) <= 2.0
        else:
            secondsfrac = daysecondsfrac
        # daysecondsfrac isn't referenced again
        assert isinstance(secondsfrac, float)
        assert abs(secondsfrac) <= 2.0

        assert isinstance(seconds, int)
        days, seconds = divmod(seconds, 24*3600)
        d += days
        s += int(seconds)    # can't overflow
        assert isinstance(s, int)
        assert abs(s) <= 2 * 24 * 3600
        # seconds isn't referenced again before redefinition

        usdouble = secondsfrac * 1e6
        assert abs(usdouble) < 2.1e6    # exact value not critical
        # secondsfrac isn't referenced again

        if isinstance(microseconds, float):
            microseconds = round(microseconds + usdouble)
            seconds, microseconds = divmod(microseconds, 1000000)
            days, seconds = divmod(seconds, 24*3600)
            d += days
            s += seconds
        else:
            microseconds = int(microseconds)
            seconds, microseconds = divmod(microseconds, 1000000)
            days, seconds = divmod(seconds, 24*3600)
            d += days
            s += seconds
            microseconds = round(microseconds + usdouble)
        assert isinstance(s, int)
        assert isinstance(microseconds, int)
        assert abs(s) <= 3 * 24 * 3600
        assert abs(microseconds) < 3.1e6

        # Just a little bit of carrying possible for microseconds and seconds.
        seconds, us = divmod(microseconds, 1000000)
        s += seconds
        days, s = divmod(s, 24*3600)
        d += days

        assert isinstance(d, int)
        assert isinstance(s, int) and 0 <= s < 24*3600
        assert isinstance(us, int) and 0 <= us < 1000000

        if abs(d) > 999999999:
            raise OverflowError("timedelta # of days is too large: %d" % d)

        self = object.__new__(cls)
        self._days = d
        self._seconds = s
        self._microseconds = us
        self._hashcode = -1
        return self

    def __repr__(self):
        args = []
        if self._days:
            args.append("days=%d" % self._days)
        if self._seconds:
            args.append("seconds=%d" % self._seconds)
        if self._microseconds:
            args.append("microseconds=%d" % self._microseconds)
        if not args:
            args.append('0')
        return "%s.%s(%s)" % (self.__class__.__module__,
                              self.__class__.__qualname__,
                              ', '.join(args))

    def __str__(self):
        mm, ss = divmod(self._seconds, 60)
        hh, mm = divmod(mm, 60)
        s = "%d:%02d:%02d" % (hh, mm, ss)
        if self._days:
            def plural(n):
                return n, abs(n) != 1 and "s" or ""
            s = ("%d day%s, " % plural(self._days)) + s
        if self._microseconds:
            s = s + ".%06d" % self._microseconds
        return s

    def total_seconds(self):
        """Total seconds in the duration."""
        return ((self.days * 86400 + self.seconds) * 10**6 +
                self.microseconds) / 10**6

    # Read-only field accessors
    @property
    def days(self):
        """days"""
        return self._days

    @property
    def seconds(self):
        """seconds"""
        return self._seconds

    @property
    def microseconds(self):
        """microseconds"""
        return self._microseconds

    def __add__(self, other):
        if isinstance(other, timedelta):
            # for CPython compatibility, we cannot use
            # our __class__ here, but need a real timedelta
            return timedelta(self._days + other._days,
                             self._seconds + other._seconds,
                             self._microseconds + other._microseconds)
        return NotImplemented

    __radd__ = __add__

    def __sub__(self, other):
        if isinstance(other, timedelta):
            # for CPython compatibility, we cannot use
            # our __class__ here, but need a real timedelta
            return timedelta(self._days - other._days,
                             self._seconds - other._seconds,
                             self._microseconds - other._microseconds)
        return NotImplemented

    def __rsub__(self, other):
        if isinstance(other, timedelta):
            return -self + other
        return NotImplemented

    def __neg__(self):
        # for CPython compatibility, we cannot use
        # our __class__ here, but need a real timedelta
        return timedelta(-self._days,
                         -self._seconds,
                         -self._microseconds)

    def __pos__(self):
        return self

    def __abs__(self):
        if self._days < 0:
            return -self
        else:
            return self

    def __mul__(self, other):
        if isinstance(other, int):
            # for CPython compatibility, we cannot use
            # our __class__ here, but need a real timedelta
            return timedelta(self._days * other,
                             self._seconds * other,
                             self._microseconds * other)
        if isinstance(other, float):
            usec = self._to_microseconds()
            a, b = other.as_integer_ratio()
            return timedelta(0, 0, _divide_and_round(usec * a, b))
        return NotImplemented

    __rmul__ = __mul__

    def _to_microseconds(self):
        return ((self._days * (24*3600) + self._seconds) * 1000000 +
                self._microseconds)

    def __floordiv__(self, other):
        if not isinstance(other, (int, timedelta)):
            return NotImplemented
        usec = self._to_microseconds()
        if isinstance(other, timedelta):
            return usec // other._to_microseconds()
        if isinstance(other, int):
            return timedelta(0, 0, usec // other)

    def __truediv__(self, other):
        if not isinstance(other, (int, float, timedelta)):
            return NotImplemented
        usec = self._to_microseconds()
        if isinstance(other, timedelta):
            return usec / other._to_microseconds()
        if isinstance(other, int):
            return timedelta(0, 0, _divide_and_round(usec, other))
        if isinstance(other, float):
            a, b = other.as_integer_ratio()
            return timedelta(0, 0, _divide_and_round(b * usec, a))

    def __mod__(self, other):
        if isinstance(other, timedelta):
            r = self._to_microseconds() % other._to_microseconds()
            return timedelta(0, 0, r)
        return NotImplemented

    def __divmod__(self, other):
        if isinstance(other, timedelta):
            q, r = divmod(self._to_microseconds(),
                          other._to_microseconds())
            return q, timedelta(0, 0, r)
        return NotImplemented

    # Comparisons of timedelta objects with other.

    def __eq__(self, other):
        if isinstance(other, timedelta):
            return self._cmp(other) == 0
        else:
            return False

    def __le__(self, other):
        if isinstance(other, timedelta):
            return self._cmp(other) <= 0
        else:
            _cmperror(self, other)

    def __lt__(self, other):
        if isinstance(other, timedelta):
            return self._cmp(other) < 0
        else:
            _cmperror(self, other)

    def __ge__(self, other):
        if isinstance(other, timedelta):
            return self._cmp(other) >= 0
        else:
            _cmperror(self, other)

    def __gt__(self, other):
        if isinstance(other, timedelta):
            return self._cmp(other) > 0
        else:
            _cmperror(self, other)

    def _cmp(self, other):
        assert isinstance(other, timedelta)
        return _cmp(self._getstate(), other._getstate())

    def __hash__(self):
        if self._hashcode == -1:
            self._hashcode = hash(self._getstate())
        return self._hashcode

    def __bool__(self):
        return (self._days != 0 or
                self._seconds != 0 or
                self._microseconds != 0)

    # Pickle support.

    def _getstate(self):
        return (self._days, self._seconds, self._microseconds)

    def __reduce__(self):
        return (self.__class__, self._getstate())

timedelta.min = timedelta(-999999999)
timedelta.max = timedelta(days=999999999, hours=23, minutes=59, seconds=59,
                          microseconds=999999)
timedelta.resolution = timedelta(microseconds=1)

class date:
    """Concrete date type.

    Constructors:

    __new__()
    fromtimestamp()
    today()
    fromordinal()

    Operators:

    __repr__, __str__
    __eq__, __le__, __lt__, __ge__, __gt__, __hash__
    __add__, __radd__, __sub__ (add/radd only with timedelta arg)

    Methods:

    timetuple()
    toordinal()
    weekday()
    isoweekday(), isocalendar(), isoformat()
    ctime()
    strftime()

    Properties (readonly):
    year, month, day
    """
    __slots__ = '_year', '_month', '_day', '_hashcode'

    def __new__(cls, year, month=None, day=None):
        """Constructor.

        Arguments:

        year, month, day (required, base 1)
        """
        if (month is None and
            isinstance(year, (bytes, str)) and len(year) == 4 and
            1 <= ord(year[2:3]) <= 12):
            # Pickle support
            if isinstance(year, str):
                try:
                    year = year.encode('latin1')
                except UnicodeEncodeError:
                    # More informative error message.
                    raise ValueError(
                        "Failed to encode latin1 string when unpickling "
                        "a date object. "
                        "pickle.load(data, encoding='latin1') is assumed.")
            self = object.__new__(cls)
            self.__setstate(year)
            self._hashcode = -1
            return self
        year, month, day = _check_date_fields(year, month, day)
        self = object.__new__(cls)
        self._year = year
        self._month = month
        self._day = day
        self._hashcode = -1
        return self

    # Additional constructors

    @classmethod
    def fromtimestamp(cls, t):
        "Construct a date from a POSIX timestamp (like time.time())."
        y, m, d, hh, mm, ss, weekday, jday, dst = _time.localtime(t)
        return cls(y, m, d)

    @classmethod
    def today(cls):
        "Construct a date from time.time()."
        t = _time.time()
        return cls.fromtimestamp(t)

    @classmethod
    def fromordinal(cls, n):
        """Construct a date from a proleptic Gregorian ordinal.

        January 1 of year 1 is day 1.  Only the year, month and day are
        non-zero in the result.
        """
        y, m, d = _ord2ymd(n)
        return cls(y, m, d)

    @classmethod
    def fromisoformat(cls, date_string):
        """Construct a date from the output of date.isoformat()."""
        if not isinstance(date_string, str):
            raise TypeError('fromisoformat: argument must be str')

        try:
            assert len(date_string) == 10
            return cls(*_parse_isoformat_date(date_string))
        except Exception:
            raise ValueError(f'Invalid isoformat string: {date_string!r}')


    # Conversions to string

    def __repr__(self):
        """Convert to formal string, for repr().

        >>> dt = datetime(2010, 1, 1)
        >>> repr(dt)
        'datetime.datetime(2010, 1, 1, 0, 0)'

        >>> dt = datetime(2010, 1, 1, tzinfo=timezone.utc)
        >>> repr(dt)
        'datetime.datetime(2010, 1, 1, 0, 0, tzinfo=datetime.timezone.utc)'
        """
        return "%s.%s(%d, %d, %d)" % (self.__class__.__module__,
                                      self.__class__.__qualname__,
                                      self._year,
                                      self._month,
                                      self._day)
    # XXX These shouldn't depend on time.localtime(), because that
    # clips the usable dates to [1970 .. 2038).  At least ctime() is
    # easily done without using strftime() -- that's better too because
    # strftime("%c", ...) is locale specific.


    def ctime(self):
        "Return ctime() style string."
        weekday = self.toordinal() % 7 or 7
        return "%s %s %2d 00:00:00 %04d" % (
            _DAYNAMES[weekday],
            _MONTHNAMES[self._month],
            self._day, self._year)

    def strftime(self, fmt):
        "Format using strftime()."
        return _wrap_strftime(self, fmt, self.timetuple())

    def __format__(self, fmt):
        if not isinstance(fmt, str):
            raise TypeError("must be str, not %s" % type(fmt).__name__)
        if len(fmt) != 0:
            return self.strftime(fmt)
        return str(self)

    def isoformat(self):
        """Return the date formatted according to ISO.

        This is 'YYYY-MM-DD'.

        References:
        - http://www.w3.org/TR/NOTE-datetime
        - http://www.cl.cam.ac.uk/~mgk25/iso-time.html
        """
        return "%04d-%02d-%02d" % (self._year, self._month, self._day)

    __str__ = isoformat

    # Read-only field accessors
    @property
    def year(self):
        """year (1-9999)"""
        return self._year

    @property
    def month(self):
        """month (1-12)"""
        return self._month

    @property
    def day(self):
        """day (1-31)"""
        return self._day

    # Standard conversions, __eq__, __le__, __lt__, __ge__, __gt__,
    # __hash__ (and helpers)

    def timetuple(self):
        "Return local time tuple compatible with time.localtime()."
        return _build_struct_time(self._year, self._month, self._day,
                                  0, 0, 0, -1)

    def toordinal(self):
        """Return proleptic Gregorian ordinal for the year, month and day.

        January 1 of year 1 is day 1.  Only the year, month and day values
        contribute to the result.
        """
        return _ymd2ord(self._year, self._month, self._day)

    def replace(self, year=None, month=None, day=None):
        """Return a new date with new values for the specified fields."""
        if year is None:
            year = self._year
        if month is None:
            month = self._month
        if day is None:
            day = self._day
        return type(self)(year, month, day)

    # Comparisons of date objects with other.

    def __eq__(self, other):
        if isinstance(other, date):
            return self._cmp(other) == 0
        return NotImplemented

    def __le__(self, other):
        if isinstance(other, date):
            return self._cmp(other) <= 0
        return NotImplemented

    def __lt__(self, other):
        if isinstance(other, date):
            return self._cmp(other) < 0
        return NotImplemented

    def __ge__(self, other):
        if isinstance(other, date):
            return self._cmp(other) >= 0
        return NotImplemented

    def __gt__(self, other):
        if isinstance(other, date):
            return self._cmp(other) > 0
        return NotImplemented

    def _cmp(self, other):
        assert isinstance(other, date)
        y, m, d = self._year, self._month, self._day
        y2, m2, d2 = other._year, other._month, other._day
        return _cmp((y, m, d), (y2, m2, d2))

    def __hash__(self):
        "Hash."
        if self._hashcode == -1:
            self._hashcode = hash(self._getstate())
        return self._hashcode

    # Computations

    def __add__(self, other):
        "Add a date to a timedelta."
        if isinstance(other, timedelta):
            o = self.toordinal() + other.days
            if 0 < o <= _MAXORDINAL:
                return date.fromordinal(o)
            raise OverflowError("result out of range")
        return NotImplemented

    __radd__ = __add__

    def __sub__(self, other):
        """Subtract two dates, or a date and a timedelta."""
        if isinstance(other, timedelta):
            return self + timedelta(-other.days)
        if isinstance(other, date):
            days1 = self.toordinal()
            days2 = other.toordinal()
            return timedelta(days1 - days2)
        return NotImplemented

    def weekday(self):
        "Return day of the week, where Monday == 0 ... Sunday == 6."
        return (self.toordinal() + 6) % 7

    # Day-of-the-week and week-of-the-year, according to ISO

    def isoweekday(self):
        "Return day of the week, where Monday == 1 ... Sunday == 7."
        # 1-Jan-0001 is a Monday
        return self.toordinal() % 7 or 7

    def isocalendar(self):
        """Return a 3-tuple containing ISO year, week number, and weekday.

        The first ISO week of the year is the (Mon-Sun) week
        containing the year's first Thursday; everything else derives
        from that.

        The first week is 1; Monday is 1 ... Sunday is 7.

        ISO calendar algorithm taken from
        http://www.phys.uu.nl/~vgent/calendar/isocalendar.htm
        (used with permission)
        """
        year = self._year
        week1monday = _isoweek1monday(year)
        today = _ymd2ord(self._year, self._month, self._day)
        # Internally, week and day have origin 0
        week, day = divmod(today - week1monday, 7)
        if week < 0:
            year -= 1
            week1monday = _isoweek1monday(year)
            week, day = divmod(today - week1monday, 7)
        elif week >= 52:
            if today >= _isoweek1monday(year+1):
                year += 1
                week = 0
        return year, week+1, day+1

    # Pickle support.

    def _getstate(self):
        yhi, ylo = divmod(self._year, 256)
        return bytes([yhi, ylo, self._month, self._day]),

    def __setstate(self, string):
        yhi, ylo, self._month, self._day = string
        self._year = yhi * 256 + ylo

    def __reduce__(self):
        return (self.__class__, self._getstate())

_date_class = date  # so functions w/ args named "date" can get at the class

date.min = date(1, 1, 1)
date.max = date(9999, 12, 31)
date.resolution = timedelta(days=1)


class tzinfo:
    """Abstract base class for time zone info classes.

    Subclasses must override the name(), utcoffset() and dst() methods.
    """
    __slots__ = ()

    def tzname(self, dt):
        "datetime -> string name of time zone."
        raise NotImplementedError("tzinfo subclass must override tzname()")

    def utcoffset(self, dt):
        "datetime -> timedelta, positive for east of UTC, negative for west of UTC"
        raise NotImplementedError("tzinfo subclass must override utcoffset()")

    def dst(self, dt):
        """datetime -> DST offset as timedelta, positive for east of UTC.

        Return 0 if DST not in effect.  utcoffset() must include the DST
        offset.
        """
        raise NotImplementedError("tzinfo subclass must override dst()")

    def fromutc(self, dt):
        "datetime in UTC -> datetime in local time."

        if not isinstance(dt, datetime):
            raise TypeError("fromutc() requires a datetime argument")
        if dt.tzinfo is not self:
            raise ValueError("dt.tzinfo is not self")

        dtoff = dt.utcoffset()
        if dtoff is None:
            raise ValueError("fromutc() requires a non-None utcoffset() "
                             "result")

        # See the long comment block at the end of this file for an
        # explanation of this algorithm.
        dtdst = dt.dst()
        if dtdst is None:
            raise ValueError("fromutc() requires a non-None dst() result")
        delta = dtoff - dtdst
        if delta:
            dt += delta
            dtdst = dt.dst()
            if dtdst is None:
                raise ValueError("fromutc(): dt.dst gave inconsistent "
                                 "results; cannot convert")
        return dt + dtdst

    # Pickle support.

    def __reduce__(self):
        getinitargs = getattr(self, "__getinitargs__", None)
        if getinitargs:
            args = getinitargs()
        else:
            args = ()
        getstate = getattr(self, "__getstate__", None)
        if getstate:
            state = getstate()
        else:
            state = getattr(self, "__dict__", None) or None
        if state is None:
            return (self.__class__, args)
        else:
            return (self.__class__, args, state)

_tzinfo_class = tzinfo

class time:
    """Time with time zone.

    Constructors:

    __new__()

    Operators:

    __repr__, __str__
    __eq__, __le__, __lt__, __ge__, __gt__, __hash__

    Methods:

    strftime()
    isoformat()
    utcoffset()
    tzname()
    dst()

    Properties (readonly):
    hour, minute, second, microsecond, tzinfo, fold
    """
    __slots__ = '_hour', '_minute', '_second', '_microsecond', '_tzinfo', '_hashcode', '_fold'

    def __new__(cls, hour=0, minute=0, second=0, microsecond=0, tzinfo=None, *, fold=0):
        """Constructor.

        Arguments:

        hour, minute (required)
        second, microsecond (default to zero)
        tzinfo (default to None)
        fold (keyword only, default to zero)
        """
        if (isinstance(hour, (bytes, str)) and len(hour) == 6 and
            ord(hour[0:1])&0x7F < 24):
            # Pickle support
            if isinstance(hour, str):
                try:
                    hour = hour.encode('latin1')
                except UnicodeEncodeError:
                    # More informative error message.
                    raise ValueError(
                        "Failed to encode latin1 string when unpickling "
                        "a time object. "
                        "pickle.load(data, encoding='latin1') is assumed.")
            self = object.__new__(cls)
            self.__setstate(hour, minute or None)
            self._hashcode = -1
            return self
        hour, minute, second, microsecond, fold = _check_time_fields(
            hour, minute, second, microsecond, fold)
        _check_tzinfo_arg(tzinfo)
        self = object.__new__(cls)
        self._hour = hour
        self._minute = minute
        self._second = second
        self._microsecond = microsecond
        self._tzinfo = tzinfo
        self._hashcode = -1
        self._fold = fold
        return self

    # Read-only field accessors
    @property
    def hour(self):
        """hour (0-23)"""
        return self._hour

    @property
    def minute(self):
        """minute (0-59)"""
        return self._minute

    @property
    def second(self):
        """second (0-59)"""
        return self._second

    @property
    def microsecond(self):
        """microsecond (0-999999)"""
        return self._microsecond

    @property
    def tzinfo(self):
        """timezone info object"""
        return self._tzinfo

    @property
    def fold(self):
        return self._fold

    # Standard conversions, __hash__ (and helpers)

    # Comparisons of time objects with other.

    def __eq__(self, other):
        if isinstance(other, time):
            return self._cmp(other, allow_mixed=True) == 0
        else:
            return False

    def __le__(self, other):
        if isinstance(other, time):
            return self._cmp(other) <= 0
        else:
            _cmperror(self, other)

    def __lt__(self, other):
        if isinstance(other, time):
            return self._cmp(other) < 0
        else:
            _cmperror(self, other)

    def __ge__(self, other):
        if isinstance(other, time):
            return self._cmp(other) >= 0
        else:
            _cmperror(self, other)

    def __gt__(self, other):
        if isinstance(other, time):
            return self._cmp(other) > 0
        else:
            _cmperror(self, other)

    def _cmp(self, other, allow_mixed=False):
        assert isinstance(other, time)
        mytz = self._tzinfo
        ottz = other._tzinfo
        myoff = otoff = None

        if mytz is ottz:
            base_compare = True
        else:
            myoff = self.utcoffset()
            otoff = other.utcoffset()
            base_compare = myoff == otoff

        if base_compare:
            return _cmp((self._hour, self._minute, self._second,
                         self._microsecond),
                        (other._hour, other._minute, other._second,
                         other._microsecond))
        if myoff is None or otoff is None:
            if allow_mixed:
                return 2 # arbitrary non-zero value
            else:
                raise TypeError("cannot compare naive and aware times")
        myhhmm = self._hour * 60 + self._minute - myoff//timedelta(minutes=1)
        othhmm = other._hour * 60 + other._minute - otoff//timedelta(minutes=1)
        return _cmp((myhhmm, self._second, self._microsecond),
                    (othhmm, other._second, other._microsecond))

    def __hash__(self):
        """Hash."""
        if self._hashcode == -1:
            if self.fold:
                t = self.replace(fold=0)
            else:
                t = self
            tzoff = t.utcoffset()
            if not tzoff:  # zero or None
                self._hashcode = hash(t._getstate()[0])
            else:
                h, m = divmod(timedelta(hours=self.hour, minutes=self.minute) - tzoff,
                              timedelta(hours=1))
                assert not m % timedelta(minutes=1), "whole minute"
                m //= timedelta(minutes=1)
                if 0 <= h < 24:
                    self._hashcode = hash(time(h, m, self.second, self.microsecond))
                else:
                    self._hashcode = hash((h, m, self.second, self.microsecond))
        return self._hashcode

    # Conversion to string

    def _tzstr(self):
        """Return formatted timezone offset (+xx:xx) or an empty string."""
        off = self.utcoffset()
        return _format_offset(off)

    def __repr__(self):
        """Convert to formal string, for repr()."""
        if self._microsecond != 0:
            s = ", %d, %d" % (self._second, self._microsecond)
        elif self._second != 0:
            s = ", %d" % self._second
        else:
            s = ""
        s= "%s.%s(%d, %d%s)" % (self.__class__.__module__,
                                self.__class__.__qualname__,
                                self._hour, self._minute, s)
        if self._tzinfo is not None:
            assert s[-1:] == ")"
            s = s[:-1] + ", tzinfo=%r" % self._tzinfo + ")"
        if self._fold:
            assert s[-1:] == ")"
            s = s[:-1] + ", fold=1)"
        return s

    def isoformat(self, timespec='auto'):
        """Return the time formatted according to ISO.

        The full format is 'HH:MM:SS.mmmmmm+zz:zz'. By default, the fractional
        part is omitted if self.microsecond == 0.

        The optional argument timespec specifies the number of additional
        terms of the time to include.
        """
        s = _format_time(self._hour, self._minute, self._second,
                          self._microsecond, timespec)
        tz = self._tzstr()
        if tz:
            s += tz
        return s

    __str__ = isoformat

    @classmethod
    def fromisoformat(cls, time_string):
        """Construct a time from the output of isoformat()."""
        if not isinstance(time_string, str):
            raise TypeError('fromisoformat: argument must be str')

        try:
            return cls(*_parse_isoformat_time(time_string))
        except Exception:
            raise ValueError(f'Invalid isoformat string: {time_string!r}')


    def strftime(self, fmt):
        """Format using strftime().  The date part of the timestamp passed
        to underlying strftime should not be used.
        """
        # The year must be >= 1000 else Python's strftime implementation
        # can raise a bogus exception.
        timetuple = (1900, 1, 1,
                     self._hour, self._minute, self._second,
                     0, 1, -1)
        return _wrap_strftime(self, fmt, timetuple)

    def __format__(self, fmt):
        if not isinstance(fmt, str):
            raise TypeError("must be str, not %s" % type(fmt).__name__)
        if len(fmt) != 0:
            return self.strftime(fmt)
        return str(self)

    # Timezone functions

    def utcoffset(self):
        """Return the timezone offset as timedelta, positive east of UTC
         (negative west of UTC)."""
        if self._tzinfo is None:
            return None
        offset = self._tzinfo.utcoffset(None)
        _check_utc_offset("utcoffset", offset)
        return offset

    def tzname(self):
        """Return the timezone name.

        Note that the name is 100% informational -- there's no requirement that
        it mean anything in particular. For example, "GMT", "UTC", "-500",
        "-5:00", "EDT", "US/Eastern", "America/New York" are all valid replies.
        """
        if self._tzinfo is None:
            return None
        name = self._tzinfo.tzname(None)
        _check_tzname(name)
        return name

    def dst(self):
        """Return 0 if DST is not in effect, or the DST offset (as timedelta
        positive eastward) if DST is in effect.

        This is purely informational; the DST offset has already been added to
        the UTC offset returned by utcoffset() if applicable, so there's no
        need to consult dst() unless you're interested in displaying the DST
        info.
        """
        if self._tzinfo is None:
            return None
        offset = self._tzinfo.dst(None)
        _check_utc_offset("dst", offset)
        return offset

    def replace(self, hour=None, minute=None, second=None, microsecond=None,
                tzinfo=True, *, fold=None):
        """Return a new time with new values for the specified fields."""
        if hour is None:
            hour = self.hour
        if minute is None:
            minute = self.minute
        if second is None:
            second = self.second
        if microsecond is None:
            microsecond = self.microsecond
        if tzinfo is True:
            tzinfo = self.tzinfo
        if fold is None:
            fold = self._fold
        return type(self)(hour, minute, second, microsecond, tzinfo, fold=fold)

    # Pickle support.

    def _getstate(self, protocol=3):
        us2, us3 = divmod(self._microsecond, 256)
        us1, us2 = divmod(us2, 256)
        h = self._hour
        if self._fold and protocol > 3:
            h += 128
        basestate = bytes([h, self._minute, self._second,
                           us1, us2, us3])
        if self._tzinfo is None:
            return (basestate,)
        else:
            return (basestate, self._tzinfo)

    def __setstate(self, string, tzinfo):
        if tzinfo is not None and not isinstance(tzinfo, _tzinfo_class):
            raise TypeError("bad tzinfo state arg")
        h, self._minute, self._second, us1, us2, us3 = string
        if h > 127:
            self._fold = 1
            self._hour = h - 128
        else:
            self._fold = 0
            self._hour = h
        self._microsecond = (((us1 << 8) | us2) << 8) | us3
        self._tzinfo = tzinfo

    def __reduce_ex__(self, protocol):
        return (time, self._getstate(protocol))

    def __reduce__(self):
        return self.__reduce_ex__(2)

_time_class = time  # so functions w/ args named "time" can get at the class

time.min = time(0, 0, 0)
time.max = time(23, 59, 59, 999999)
time.resolution = timedelta(microseconds=1)

class datetime(date):
    """datetime(year, month, day[, hour[, minute[, second[, microsecond[,tzinfo]]]]])

    The year, month and day arguments are required. tzinfo may be None, or an
    instance of a tzinfo subclass. The remaining arguments may be ints.
    """
    __slots__ = date.__slots__ + time.__slots__

    def __new__(cls, year, month=None, day=None, hour=0, minute=0, second=0,
                microsecond=0, tzinfo=None, *, fold=0):
        if (isinstance(year, (bytes, str)) and len(year) == 10 and
            1 <= ord(year[2:3])&0x7F <= 12):
            # Pickle support
            if isinstance(year, str):
                try:
                    year = bytes(year, 'latin1')
                except UnicodeEncodeError:
                    # More informative error message.
                    raise ValueError(
                        "Failed to encode latin1 string when unpickling "
                        "a datetime object. "
                        "pickle.load(data, encoding='latin1') is assumed.")
            self = object.__new__(cls)
            self.__setstate(year, month)
            self._hashcode = -1
            return self
        year, month, day = _check_date_fields(year, month, day)
        hour, minute, second, microsecond, fold = _check_time_fields(
            hour, minute, second, microsecond, fold)
        _check_tzinfo_arg(tzinfo)
        self = object.__new__(cls)
        self._year = year
        self._month = month
        self._day = day
        self._hour = hour
        self._minute = minute
        self._second = second
        self._microsecond = microsecond
        self._tzinfo = tzinfo
        self._hashcode = -1
        self._fold = fold
        return self

    # Read-only field accessors
    @property
    def hour(self):
        """hour (0-23)"""
        return self._hour

    @property
    def minute(self):
        """minute (0-59)"""
        return self._minute

    @property
    def second(self):
        """second (0-59)"""
        return self._second

    @property
    def microsecond(self):
        """microsecond (0-999999)"""
        return self._microsecond

    @property
    def tzinfo(self):
        """timezone info object"""
        return self._tzinfo

    @property
    def fold(self):
        return self._fold

    @classmethod
    def _fromtimestamp(cls, t, utc, tz):
        """Construct a datetime from a POSIX timestamp (like time.time()).

        A timezone info object may be passed in as well.
        """
        frac, t = _math.modf(t)
        us = round(frac * 1e6)
        if us >= 1000000:
            t += 1
            us -= 1000000
        elif us < 0:
            t -= 1
            us += 1000000

        converter = _time.gmtime if utc else _time.localtime
        y, m, d, hh, mm, ss, weekday, jday, dst = converter(t)
        ss = min(ss, 59)    # clamp out leap seconds if the platform has them
        result = cls(y, m, d, hh, mm, ss, us, tz)
        if tz is None:
            # As of version 2015f max fold in IANA database is
            # 23 hours at 1969-09-30 13:00:00 in Kwajalein.
            # Let's probe 24 hours in the past to detect a transition:
            max_fold_seconds = 24 * 3600

            # On Windows localtime_s throws an OSError for negative values,
            # thus we can't perform fold detection for values of time less
            # than the max time fold. See comments in _datetimemodule's
            # version of this method for more details.
            if t < max_fold_seconds and sys.platform.startswith("win"):
                return result

            y, m, d, hh, mm, ss = converter(t - max_fold_seconds)[:6]
            probe1 = cls(y, m, d, hh, mm, ss, us, tz)
            trans = result - probe1 - timedelta(0, max_fold_seconds)
            if trans.days < 0:
                y, m, d, hh, mm, ss = converter(t + trans // timedelta(0, 1))[:6]
                probe2 = cls(y, m, d, hh, mm, ss, us, tz)
                if probe2 == result:
                    result._fold = 1
        else:
            result = tz.fromutc(result)
        return result

    @classmethod
    def fromtimestamp(cls, t, tz=None):
        """Construct a datetime from a POSIX timestamp (like time.time()).

        A timezone info object may be passed in as well.
        """
        _check_tzinfo_arg(tz)

        return cls._fromtimestamp(t, tz is not None, tz)

    @classmethod
    def utcfromtimestamp(cls, t):
        """Construct a naive UTC datetime from a POSIX timestamp."""
        return cls._fromtimestamp(t, True, None)

    @classmethod
    def now(cls, tz=None):
        "Construct a datetime from time.time() and optional time zone info."
        t = _time.time()
        return cls.fromtimestamp(t, tz)

    @classmethod
    def utcnow(cls):
        "Construct a UTC datetime from time.time()."
        t = _time.time()
        return cls.utcfromtimestamp(t)

    @classmethod
    def combine(cls, date, time, tzinfo=True):
        "Construct a datetime from a given date and a given time."
        if not isinstance(date, _date_class):
            raise TypeError("date argument must be a date instance")
        if not isinstance(time, _time_class):
            raise TypeError("time argument must be a time instance")
        if tzinfo is True:
            tzinfo = time.tzinfo
        return cls(date.year, date.month, date.day,
                   time.hour, time.minute, time.second, time.microsecond,
                   tzinfo, fold=time.fold)

    @classmethod
    def fromisoformat(cls, date_string):
        """Construct a datetime from the output of datetime.isoformat()."""
        if not isinstance(date_string, str):
            raise TypeError('fromisoformat: argument must be str')

        # Split this at the separator
        dstr = date_string[0:10]
        tstr = date_string[11:]

        try:
            date_components = _parse_isoformat_date(dstr)
        except ValueError:
            raise ValueError(f'Invalid isoformat string: {date_string!r}')

        if tstr:
            try:
                time_components = _parse_isoformat_time(tstr)
            except ValueError:
                raise ValueError(f'Invalid isoformat string: {date_string!r}')
        else:
            time_components = [0, 0, 0, 0, None]

        return cls(*(date_components + time_components))

    def timetuple(self):
        "Return local time tuple compatible with time.localtime()."
        dst = self.dst()
        if dst is None:
            dst = -1
        elif dst:
            dst = 1
        else:
            dst = 0
        return _build_struct_time(self.year, self.month, self.day,
                                  self.hour, self.minute, self.second,
                                  dst)

    def _mktime(self):
        """Return integer POSIX timestamp."""
        epoch = datetime(1970, 1, 1)
        max_fold_seconds = 24 * 3600
        t = (self - epoch) // timedelta(0, 1)
        def local(u):
            y, m, d, hh, mm, ss = _time.localtime(u)[:6]
            return (datetime(y, m, d, hh, mm, ss) - epoch) // timedelta(0, 1)

        # Our goal is to solve t = local(u) for u.
        a = local(t) - t
        u1 = t - a
        t1 = local(u1)
        if t1 == t:
            # We found one solution, but it may not be the one we need.
            # Look for an earlier solution (if `fold` is 0), or a
            # later one (if `fold` is 1).
            u2 = u1 + (-max_fold_seconds, max_fold_seconds)[self.fold]
            b = local(u2) - u2
            if a == b:
                return u1
        else:
            b = t1 - u1
            assert a != b
        u2 = t - b
        t2 = local(u2)
        if t2 == t:
            return u2
        if t1 == t:
            return u1
        # We have found both offsets a and b, but neither t - a nor t - b is
        # a solution.  This means t is in the gap.
        return (max, min)[self.fold](u1, u2)


    def timestamp(self):
        "Return POSIX timestamp as float"
        if self._tzinfo is None:
            s = self._mktime()
            return s + self.microsecond / 1e6
        else:
            return (self - _EPOCH).total_seconds()

    def utctimetuple(self):
        "Return UTC time tuple compatible with time.gmtime()."
        offset = self.utcoffset()
        if offset:
            self -= offset
        y, m, d = self.year, self.month, self.day
        hh, mm, ss = self.hour, self.minute, self.second
        return _build_struct_time(y, m, d, hh, mm, ss, 0)

    def date(self):
        "Return the date part."
        return date(self._year, self._month, self._day)

    def time(self):
        "Return the time part, with tzinfo None."
        return time(self.hour, self.minute, self.second, self.microsecond, fold=self.fold)

    def timetz(self):
        "Return the time part, with same tzinfo."
        return time(self.hour, self.minute, self.second, self.microsecond,
                    self._tzinfo, fold=self.fold)

    def replace(self, year=None, month=None, day=None, hour=None,
                minute=None, second=None, microsecond=None, tzinfo=True,
                *, fold=None):
        """Return a new datetime with new values for the specified fields."""
        if year is None:
            year = self.year
        if month is None:
            month = self.month
        if day is None:
            day = self.day
        if hour is None:
            hour = self.hour
        if minute is None:
            minute = self.minute
        if second is None:
            second = self.second
        if microsecond is None:
            microsecond = self.microsecond
        if tzinfo is True:
            tzinfo = self.tzinfo
        if fold is None:
            fold = self.fold
        return type(self)(year, month, day, hour, minute, second,
                          microsecond, tzinfo, fold=fold)

    def _local_timezone(self):
        if self.tzinfo is None:
            ts = self._mktime()
        else:
            ts = (self - _EPOCH) // timedelta(seconds=1)
        localtm = _time.localtime(ts)
        local = datetime(*localtm[:6])
        try:
            # Extract TZ data if available
            gmtoff = localtm.tm_gmtoff
            zone = localtm.tm_zone
        except AttributeError:
            delta = local - datetime(*_time.gmtime(ts)[:6])
            zone = _time.strftime('%Z', localtm)
            tz = timezone(delta, zone)
        else:
            tz = timezone(timedelta(seconds=gmtoff), zone)
        return tz

    def astimezone(self, tz=None):
        if tz is None:
            tz = self._local_timezone()
        elif not isinstance(tz, tzinfo):
            raise TypeError("tz argument must be an instance of tzinfo")

        mytz = self.tzinfo
        if mytz is None:
            mytz = self._local_timezone()
            myoffset = mytz.utcoffset(self)
        else:
            myoffset = mytz.utcoffset(self)
            if myoffset is None:
                mytz = self.replace(tzinfo=None)._local_timezone()
                myoffset = mytz.utcoffset(self)

        if tz is mytz:
            return self

        # Convert self to UTC, and attach the new time zone object.
        utc = (self - myoffset).replace(tzinfo=tz)

        # Convert from UTC to tz's local time.
        return tz.fromutc(utc)

    # Ways to produce a string.

    def ctime(self):
        "Return ctime() style string."
        weekday = self.toordinal() % 7 or 7
        return "%s %s %2d %02d:%02d:%02d %04d" % (
            _DAYNAMES[weekday],
            _MONTHNAMES[self._month],
            self._day,
            self._hour, self._minute, self._second,
            self._year)

    def isoformat(self, sep='T', timespec='auto'):
        """Return the time formatted according to ISO.

        The full format looks like 'YYYY-MM-DD HH:MM:SS.mmmmmm'.
        By default, the fractional part is omitted if self.microsecond == 0.

        If self.tzinfo is not None, the UTC offset is also attached, giving
        giving a full format of 'YYYY-MM-DD HH:MM:SS.mmmmmm+HH:MM'.

        Optional argument sep specifies the separator between date and
        time, default 'T'.

        The optional argument timespec specifies the number of additional
        terms of the time to include.
        """
        s = ("%04d-%02d-%02d%c" % (self._year, self._month, self._day, sep) +
             _format_time(self._hour, self._minute, self._second,
                          self._microsecond, timespec))

        off = self.utcoffset()
        tz = _format_offset(off)
        if tz:
            s += tz

        return s

    def __repr__(self):
        """Convert to formal string, for repr()."""
        L = [self._year, self._month, self._day,  # These are never zero
             self._hour, self._minute, self._second, self._microsecond]
        if L[-1] == 0:
            del L[-1]
        if L[-1] == 0:
            del L[-1]
        s = "%s.%s(%s)" % (self.__class__.__module__,
                           self.__class__.__qualname__,
                           ", ".join(map(str, L)))
        if self._tzinfo is not None:
            assert s[-1:] == ")"
            s = s[:-1] + ", tzinfo=%r" % self._tzinfo + ")"
        if self._fold:
            assert s[-1:] == ")"
            s = s[:-1] + ", fold=1)"
        return s

    def __str__(self):
        "Convert to string, for str()."
        return self.isoformat(sep=' ')

    @classmethod
    def strptime(cls, date_string, format):
        'string, format -> new datetime parsed from a string (like time.strptime()).'
        import _strptime
        return _strptime._strptime_datetime(cls, date_string, format)

    def utcoffset(self):
        """Return the timezone offset as timedelta positive east of UTC (negative west of
        UTC)."""
        if self._tzinfo is None:
            return None
        offset = self._tzinfo.utcoffset(self)
        _check_utc_offset("utcoffset", offset)
        return offset

    def tzname(self):
        """Return the timezone name.

        Note that the name is 100% informational -- there's no requirement that
        it mean anything in particular. For example, "GMT", "UTC", "-500",
        "-5:00", "EDT", "US/Eastern", "America/New York" are all valid replies.
        """
        if self._tzinfo is None:
            return None
        name = self._tzinfo.tzname(self)
        _check_tzname(name)
        return name

    def dst(self):
        """Return 0 if DST is not in effect, or the DST offset (as timedelta
        positive eastward) if DST is in effect.

        This is purely informational; the DST offset has already been added to
        the UTC offset returned by utcoffset() if applicable, so there's no
        need to consult dst() unless you're interested in displaying the DST
        info.
        """
        if self._tzinfo is None:
            return None
        offset = self._tzinfo.dst(self)
        _check_utc_offset("dst", offset)
        return offset

    # Comparisons of datetime objects with other.

    def __eq__(self, other):
        if isinstance(other, datetime):
            return self._cmp(other, allow_mixed=True) == 0
        elif not isinstance(other, date):
            return NotImplemented
        else:
            return False

    def __le__(self, other):
        if isinstance(other, datetime):
            return self._cmp(other) <= 0
        elif not isinstance(other, date):
            return NotImplemented
        else:
            _cmperror(self, other)

    def __lt__(self, other):
        if isinstance(other, datetime):
            return self._cmp(other) < 0
        elif not isinstance(other, date):
            return NotImplemented
        else:
            _cmperror(self, other)

    def __ge__(self, other):
        if isinstance(other, datetime):
            return self._cmp(other) >= 0
        elif not isinstance(other, date):
            return NotImplemented
        else:
            _cmperror(self, other)

    def __gt__(self, other):
        if isinstance(other, datetime):
            return self._cmp(other) > 0
        elif not isinstance(other, date):
            return NotImplemented
        else:
            _cmperror(self, other)

    def _cmp(self, other, allow_mixed=False):
        assert isinstance(other, datetime)
        mytz = self._tzinfo
        ottz = other._tzinfo
        myoff = otoff = None

        if mytz is ottz:
            base_compare = True
        else:
            myoff = self.utcoffset()
            otoff = other.utcoffset()
            # Assume that allow_mixed means that we are called from __eq__
            if allow_mixed:
                if myoff != self.replace(fold=not self.fold).utcoffset():
                    return 2
                if otoff != other.replace(fold=not other.fold).utcoffset():
                    return 2
            base_compare = myoff == otoff

        if base_compare:
            return _cmp((self._year, self._month, self._day,
                         self._hour, self._minute, self._second,
                         self._microsecond),
                        (other._year, other._month, other._day,
                         other._hour, other._minute, other._second,
                         other._microsecond))
        if myoff is None or otoff is None:
            if allow_mixed:
                return 2 # arbitrary non-zero value
            else:
                raise TypeError("cannot compare naive and aware datetimes")
        # XXX What follows could be done more efficiently...
        diff = self - other     # this will take offsets into account
        if diff.days < 0:
            return -1
        return diff and 1 or 0

    def __add__(self, other):
        "Add a datetime and a timedelta."
        if not isinstance(other, timedelta):
            return NotImplemented
        delta = timedelta(self.toordinal(),
                          hours=self._hour,
                          minutes=self._minute,
                          seconds=self._second,
                          microseconds=self._microsecond)
        delta += other
        hour, rem = divmod(delta.seconds, 3600)
        minute, second = divmod(rem, 60)
        if 0 < delta.days <= _MAXORDINAL:
            return datetime.combine(date.fromordinal(delta.days),
                                    time(hour, minute, second,
                                         delta.microseconds,
                                         tzinfo=self._tzinfo))
        raise OverflowError("result out of range")

    __radd__ = __add__

    def __sub__(self, other):
        "Subtract two datetimes, or a datetime and a timedelta."
        if not isinstance(other, datetime):
            if isinstance(other, timedelta):
                return self + -other
            return NotImplemented

        days1 = self.toordinal()
        days2 = other.toordinal()
        secs1 = self._second + self._minute * 60 + self._hour * 3600
        secs2 = other._second + other._minute * 60 + other._hour * 3600
        base = timedelta(days1 - days2,
                         secs1 - secs2,
                         self._microsecond - other._microsecond)
        if self._tzinfo is other._tzinfo:
            return base
        myoff = self.utcoffset()
        otoff = other.utcoffset()
        if myoff == otoff:
            return base
        if myoff is None or otoff is None:
            raise TypeError("cannot mix naive and timezone-aware time")
        return base + otoff - myoff

    def __hash__(self):
        if self._hashcode == -1:
            if self.fold:
                t = self.replace(fold=0)
            else:
                t = self
            tzoff = t.utcoffset()
            if tzoff is None:
                self._hashcode = hash(t._getstate()[0])
            else:
                days = _ymd2ord(self.year, self.month, self.day)
                seconds = self.hour * 3600 + self.minute * 60 + self.second
                self._hashcode = hash(timedelta(days, seconds, self.microsecond) - tzoff)
        return self._hashcode

    # Pickle support.

    def _getstate(self, protocol=3):
        yhi, ylo = divmod(self._year, 256)
        us2, us3 = divmod(self._microsecond, 256)
        us1, us2 = divmod(us2, 256)
        m = self._month
        if self._fold and protocol > 3:
            m += 128
        basestate = bytes([yhi, ylo, m, self._day,
                           self._hour, self._minute, self._second,
                           us1, us2, us3])
        if self._tzinfo is None:
            return (basestate,)
        else:
            return (basestate, self._tzinfo)

    def __setstate(self, string, tzinfo):
        if tzinfo is not None and not isinstance(tzinfo, _tzinfo_class):
            raise TypeError("bad tzinfo state arg")
        (yhi, ylo, m, self._day, self._hour,
         self._minute, self._second, us1, us2, us3) = string
        if m > 127:
            self._fold = 1
            self._month = m - 128
        else:
            self._fold = 0
            self._month = m
        self._year = yhi * 256 + ylo
        self._microsecond = (((us1 << 8) | us2) << 8) | us3
        self._tzinfo = tzinfo

    def __reduce_ex__(self, protocol):
        return (self.__class__, self._getstate(protocol))

    def __reduce__(self):
        return self.__reduce_ex__(2)


datetime.min = datetime(1, 1, 1)
datetime.max = datetime(9999, 12, 31, 23, 59, 59, 999999)
datetime.resolution = timedelta(microseconds=1)


def _isoweek1monday(year):
    # Helper to calculate the day number of the Monday starting week 1
    # XXX This could be done more efficiently
    THURSDAY = 3
    firstday = _ymd2ord(year, 1, 1)
    firstweekday = (firstday + 6) % 7  # See weekday() above
    week1monday = firstday - firstweekday
    if firstweekday > THURSDAY:
        week1monday += 7
    return week1monday

class timezone(tzinfo):
    __slots__ = '_offset', '_name'

    # Sentinel value to disallow None
    _Omitted = object()
    def __new__(cls, offset, name=_Omitted):
        if not isinstance(offset, timedelta):
            raise TypeError("offset must be a timedelta")
        if name is cls._Omitted:
            if not offset:
                return cls.utc
            name = None
        elif not isinstance(name, str):
            raise TypeError("name must be a string")
        if not cls._minoffset <= offset <= cls._maxoffset:
            raise ValueError("offset must be a timedelta "
                             "strictly between -timedelta(hours=24) and "
                             "timedelta(hours=24).")
        return cls._create(offset, name)

    @classmethod
    def _create(cls, offset, name=None):
        self = tzinfo.__new__(cls)
        self._offset = offset
        self._name = name
        return self

    def __getinitargs__(self):
        """pickle support"""
        if self._name is None:
            return (self._offset,)
        return (self._offset, self._name)

    def __eq__(self, other):
        if type(other) != timezone:
            return False
        return self._offset == other._offset

    def __hash__(self):
        return hash(self._offset)

    def __repr__(self):
        """Convert to formal string, for repr().

        >>> tz = timezone.utc
        >>> repr(tz)
        'datetime.timezone.utc'
        >>> tz = timezone(timedelta(hours=-5), 'EST')
        >>> repr(tz)
        "datetime.timezone(datetime.timedelta(-1, 68400), 'EST')"
        """
        if self is self.utc:
            return 'datetime.timezone.utc'
        if self._name is None:
            return "%s.%s(%r)" % (self.__class__.__module__,
                                  self.__class__.__qualname__,
                                  self._offset)
        return "%s.%s(%r, %r)" % (self.__class__.__module__,
                                  self.__class__.__qualname__,
                                  self._offset, self._name)

    def __str__(self):
        return self.tzname(None)

    def utcoffset(self, dt):
        if isinstance(dt, datetime) or dt is None:
            return self._offset
        raise TypeError("utcoffset() argument must be a datetime instance"
                        " or None")

    def tzname(self, dt):
        if isinstance(dt, datetime) or dt is None:
            if self._name is None:
                return self._name_from_offset(self._offset)
            return self._name
        raise TypeError("tzname() argument must be a datetime instance"
                        " or None")

    def dst(self, dt):
        if isinstance(dt, datetime) or dt is None:
            return None
        raise TypeError("dst() argument must be a datetime instance"
                        " or None")

    def fromutc(self, dt):
        if isinstance(dt, datetime):
            if dt.tzinfo is not self:
                raise ValueError("fromutc: dt.tzinfo "
                                 "is not self")
            return dt + self._offset
        raise TypeError("fromutc() argument must be a datetime instance"
                        " or None")

    _maxoffset = timedelta(hours=23, minutes=59)
    _minoffset = -_maxoffset

    @staticmethod
    def _name_from_offset(delta):
        if not delta:
            return 'UTC'
        if delta < timedelta(0):
            sign = '-'
            delta = -delta
        else:
            sign = '+'
        hours, rest = divmod(delta, timedelta(hours=1))
        minutes, rest = divmod(rest, timedelta(minutes=1))
        seconds = rest.seconds
        microseconds = rest.microseconds
        if microseconds:
            return (f'UTC{sign}{hours:02d}:{minutes:02d}:{seconds:02d}'
                    f'.{microseconds:06d}')
        if seconds:
            return f'UTC{sign}{hours:02d}:{minutes:02d}:{seconds:02d}'
        return f'UTC{sign}{hours:02d}:{minutes:02d}'

timezone.utc = timezone._create(timedelta(0))
timezone.min = timezone._create(timezone._minoffset)
timezone.max = timezone._create(timezone._maxoffset)
_EPOCH = datetime(1970, 1, 1, tzinfo=timezone.utc)

# Some time zone algebra.  For a datetime x, let
#     x.n = x stripped of its timezone -- its naive time.
#     x.o = x.utcoffset(), and assuming that doesn't raise an exception or
#           return None
#     x.d = x.dst(), and assuming that doesn't raise an exception or
#           return None
#     x.s = x's standard offset, x.o - x.d
#
# Now some derived rules, where k is a duration (timedelta).
#
# 1. x.o = x.s + x.d
#    This follows from the definition of x.s.
#
# 2. If x and y have the same tzinfo member, x.s = y.s.
#    This is actually a requirement, an assumption we need to make about
#    sane tzinfo classes.
#
# 3. The naive UTC time corresponding to x is x.n - x.o.
#    This is again a requirement for a sane tzinfo class.
#
# 4. (x+k).s = x.s
#    This follows from #2, and that datimetimetz+timedelta preserves tzinfo.
#
# 5. (x+k).n = x.n + k
#    Again follows from how arithmetic is defined.
#
# Now we can explain tz.fromutc(x).  Let's assume it's an interesting case
# (meaning that the various tzinfo methods exist, and don't blow up or return
# None when called).
#
# The function wants to return a datetime y with timezone tz, equivalent to x.
# x is already in UTC.
#
# By #3, we want
#
#     y.n - y.o = x.n                             [1]
#
# The algorithm starts by attaching tz to x.n, and calling that y.  So
# x.n = y.n at the start.  Then it wants to add a duration k to y, so that [1]
# becomes true; in effect, we want to solve [2] for k:
#
#    (y+k).n - (y+k).o = x.n                      [2]
#
# By #1, this is the same as
#
#    (y+k).n - ((y+k).s + (y+k).d) = x.n          [3]
#
# By #5, (y+k).n = y.n + k, which equals x.n + k because x.n=y.n at the start.
# Substituting that into [3],
#
#    x.n + k - (y+k).s - (y+k).d = x.n; the x.n terms cancel, leaving
#    k - (y+k).s - (y+k).d = 0; rearranging,
#    k = (y+k).s - (y+k).d; by #4, (y+k).s == y.s, so
#    k = y.s - (y+k).d
#
# On the RHS, (y+k).d can't be computed directly, but y.s can be, and we
# approximate k by ignoring the (y+k).d term at first.  Note that k can't be
# very large, since all offset-returning methods return a duration of magnitude
# less than 24 hours.  For that reason, if y is firmly in std time, (y+k).d must
# be 0, so ignoring it has no consequence then.
#
# In any case, the new value is
#
#     z = y + y.s                                 [4]
#
# It's helpful to step back at look at [4] from a higher level:  it's simply
# mapping from UTC to tz's standard time.
#
# At this point, if
#
#     z.n - z.o = x.n                             [5]
#
# we have an equivalent time, and are almost done.  The insecurity here is
# at the start of daylight time.  Picture US Eastern for concreteness.  The wall
# time jumps from 1:59 to 3:00, and wall hours of the form 2:MM don't make good
# sense then.  The docs ask that an Eastern tzinfo class consider such a time to
# be EDT (because it's "after 2"), which is a redundant spelling of 1:MM EST
# on the day DST starts.  We want to return the 1:MM EST spelling because that's
# the only spelling that makes sense on the local wall clock.
#
# In fact, if [5] holds at this point, we do have the standard-time spelling,
# but that takes a bit of proof.  We first prove a stronger result.  What's the
# difference between the LHS and RHS of [5]?  Let
#
#     diff = x.n - (z.n - z.o)                    [6]
#
# Now
#     z.n =                       by [4]
#     (y + y.s).n =               by #5
#     y.n + y.s =                 since y.n = x.n
#     x.n + y.s =                 since z and y are have the same tzinfo member,
#                                     y.s = z.s by #2
#     x.n + z.s
#
# Plugging that back into [6] gives
#
#     diff =
#     x.n - ((x.n + z.s) - z.o) =     expanding
#     x.n - x.n - z.s + z.o =         cancelling
#     - z.s + z.o =                   by #2
#     z.d
#
# So diff = z.d.
#
# If [5] is true now, diff = 0, so z.d = 0 too, and we have the standard-time
# spelling we wanted in the endcase described above.  We're done.  Contrarily,
# if z.d = 0, then we have a UTC equivalent, and are also done.
#
# If [5] is not true now, diff = z.d != 0, and z.d is the offset we need to
# add to z (in effect, z is in tz's standard time, and we need to shift the
# local clock into tz's daylight time).
#
# Let
#
#     z' = z + z.d = z + diff                     [7]
#
# and we can again ask whether
#
#     z'.n - z'.o = x.n                           [8]
#
# If so, we're done.  If not, the tzinfo class is insane, according to the
# assumptions we've made.  This also requires a bit of proof.  As before, let's
# compute the difference between the LHS and RHS of [8] (and skipping some of
# the justifications for the kinds of substitutions we've done several times
# already):
#
#     diff' = x.n - (z'.n - z'.o) =           replacing z'.n via [7]
#             x.n  - (z.n + diff - z'.o) =    replacing diff via [6]
#             x.n - (z.n + x.n - (z.n - z.o) - z'.o) =
#             x.n - z.n - x.n + z.n - z.o + z'.o =    cancel x.n
#             - z.n + z.n - z.o + z'.o =              cancel z.n
#             - z.o + z'.o =                      #1 twice
#             -z.s - z.d + z'.s + z'.d =          z and z' have same tzinfo
#             z'.d - z.d
#
# So z' is UTC-equivalent to x iff z'.d = z.d at this point.  If they are equal,
# we've found the UTC-equivalent so are done.  In fact, we stop with [7] and
# return z', not bothering to compute z'.d.
#
# How could z.d and z'd differ?  z' = z + z.d [7], so merely moving z' by
# a dst() offset, and starting *from* a time already in DST (we know z.d != 0),
# would have to change the result dst() returns:  we start in DST, and moving
# a little further into it takes us out of DST.
#
# There isn't a sane case where this can happen.  The closest it gets is at
# the end of DST, where there's an hour in UTC with no spelling in a hybrid
# tzinfo class.  In US Eastern, that's 5:MM UTC = 0:MM EST = 1:MM EDT.  During
# that hour, on an Eastern clock 1:MM is taken as being in standard time (6:MM
# UTC) because the docs insist on that, but 0:MM is taken as being in daylight
# time (4:MM UTC).  There is no local time mapping to 5:MM UTC.  The local
# clock jumps from 1:59 back to 1:00 again, and repeats the 1:MM hour in
# standard time.  Since that's what the local clock *does*, we want to map both
# UTC hours 5:MM and 6:MM to 1:MM Eastern.  The result is ambiguous
# in local time, but so it goes -- it's the way the local clock works.
#
# When x = 5:MM UTC is the input to this algorithm, x.o=0, y.o=-5 and y.d=0,
# so z=0:MM.  z.d=60 (minutes) then, so [5] doesn't hold and we keep going.
# z' = z + z.d = 1:MM then, and z'.d=0, and z'.d - z.d = -60 != 0 so [8]
# (correctly) concludes that z' is not UTC-equivalent to x.
#
# Because we know z.d said z was in daylight time (else [5] would have held and
# we would have stopped then), and we know z.d != z'.d (else [8] would have held
# and we have stopped then), and there are only 2 possible values dst() can
# return in Eastern, it follows that z'.d must be 0 (which it is in the example,
# but the reasoning doesn't depend on the example -- it depends on there being
# two possible dst() outcomes, one zero and the other non-zero).  Therefore
# z' must be in standard time, and is the spelling we want in this case.
#
# Note again that z' is not UTC-equivalent as far as the hybrid tzinfo class is
# concerned (because it takes z' as being in standard time rather than the
# daylight time we intend here), but returning it gives the real-life "local
# clock repeats an hour" behavior when mapping the "unspellable" UTC hour into
# tz.
#
# When the input is 6:MM, z=1:MM and z.d=0, and we stop at once, again with
# the 1:MM standard time spelling we want.
#
# So how can this break?  One of the assumptions must be violated.  Two
# possibilities:
#
# 1) [2] effectively says that y.s is invariant across all y belong to a given
#    time zone.  This isn't true if, for political reasons or continental drift,
#    a region decides to change its base offset from UTC.
#
# 2) There may be versions of "double daylight" time where the tail end of
#    the analysis gives up a step too early.  I haven't thought about that
#    enough to say.
#
# In any case, it's clear that the default fromutc() is strong enough to handle
# "almost all" time zones:  so long as the standard offset is invariant, it
# doesn't matter if daylight time transition points change from year to year, or
# if daylight time is skipped in some years; it doesn't matter how large or
# small dst() may get within its bounds; and it doesn't even matter if some
# perverse time zone returns a negative dst()).  So a breaking case must be
# pretty bizarre, and a tzinfo subclass can override fromutc() if it is.

try:
    from _datetime import *
except ImportError:
    pass
else:
    # Clean up unused names
    del (_DAYNAMES, _DAYS_BEFORE_MONTH, _DAYS_IN_MONTH, _DI100Y, _DI400Y,
         _DI4Y, _EPOCH, _MAXORDINAL, _MONTHNAMES, _build_struct_time,
         _check_date_fields, _check_int_field, _check_time_fields,
         _check_tzinfo_arg, _check_tzname, _check_utc_offset, _cmp, _cmperror,
         _date_class, _days_before_month, _days_before_year, _days_in_month,
         _format_time, _format_offset, _is_leap, _isoweek1monday, _math,
         _ord2ymd, _time, _time_class, _tzinfo_class, _wrap_strftime, _ymd2ord,
         _divide_and_round, _parse_isoformat_date, _parse_isoformat_time,
         _parse_hh_mm_ss_ff)
    # XXX Since import * above excludes names that start with _,
    # docstring does not get overwritten. In the future, it may be
    # appropriate to maintain a single module level docstring and
    # remove the following line.
    from _datetime import __doc__