PEP 3114: rename .next() to .__next__() and add next() builtin.

61 files changed, 335 insertions, 308 deletions

diff --git a/Lib/StringIO.py b/Lib/StringIO.py
index 189d368f01..815bce6b16 100644
--- a/Lib/StringIO.py
+++ b/Lib/StringIO.py
@@ -64,10 +64,10 @@ class StringIO:
     def __iter__(self):
         return self
 
-    def next(self):
+    def __next__(self):
         """A file object is its own iterator, for example iter(f) returns f
         (unless f is closed). When a file is used as an iterator, typically
-        in a for loop (for example, for line in f: print line), the next()
+        in a for loop (for example, for line in f: print line), the __next__()
         method is called repeatedly. This method returns the next input line,
         or raises StopIteration when EOF is hit.
         """
diff --git a/Lib/UserDict.py b/Lib/UserDict.py
index 91508d8201..bcee543bab 100644
--- a/Lib/UserDict.py
+++ b/Lib/UserDict.py
@@ -139,7 +139,7 @@ class DictMixin:
         return value
     def popitem(self):
         try:
-            k, v = self.iteritems().next()
+            k, v = next(self.iteritems())
         except StopIteration:
             raise KeyError, 'container is empty'
         del self[k]
diff --git a/Lib/codecs.py b/Lib/codecs.py
index 185ad42622..d340725d7b 100644
--- a/Lib/codecs.py
+++ b/Lib/codecs.py
@@ -600,7 +600,7 @@ class StreamReader(Codec):
         self.reset()
         self.stream.seek(offset, whence)
 
-    def next(self):
+    def __next__(self):
 
         """ Return the next decoded line from the input stream."""
         line = self.readline()
@@ -669,10 +669,10 @@ class StreamReaderWriter:
 
         return self.reader.readlines(sizehint)
 
-    def next(self):
+    def __next__(self):
 
         """ Return the next decoded line from the input stream."""
-        return self.reader.next()
+        return next(self.reader)
 
     def __iter__(self):
         return self
@@ -782,10 +782,10 @@ class StreamRecoder:
         data, bytesencoded = self.encode(data, self.errors)
         return data.splitlines(1)
 
-    def next(self):
+    def __next__(self):
 
         """ Return the next decoded line from the input stream."""
-        data = self.reader.next()
+        data = next(self.reader)
         data, bytesencoded = self.encode(data, self.errors)
         return data
 
diff --git a/Lib/contextlib.py b/Lib/contextlib.py
index 731bf8f868..6605bea237 100644
--- a/Lib/contextlib.py
+++ b/Lib/contextlib.py
@@ -12,14 +12,14 @@ class GeneratorContextManager(object):
 
     def __enter__(self):
         try:
-            return self.gen.next()
+            return next(self.gen)
         except StopIteration:
             raise RuntimeError("generator didn't yield")
 
     def __exit__(self, type, value, traceback):
         if type is None:
             try:
-                self.gen.next()
+                next(self.gen)
             except StopIteration:
                 return
             else:
diff --git a/Lib/csv.py b/Lib/csv.py
index 92e4666032..45570f74c0 100644
--- a/Lib/csv.py
+++ b/Lib/csv.py
@@ -79,17 +79,17 @@ class DictReader:
     def __iter__(self):
         return self
 
-    def next(self):
-        row = self.reader.next()
+    def __next__(self):
+        row = next(self.reader)
         if self.fieldnames is None:
             self.fieldnames = row
-            row = self.reader.next()
+            row = next(self.reader)
 
         # unlike the basic reader, we prefer not to return blanks,
         # because we will typically wind up with a dict full of None
         # values
         while row == []:
-            row = self.reader.next()
+            row = next(self.reader)
         d = dict(zip(self.fieldnames, row))
         lf = len(self.fieldnames)
         lr = len(row)
@@ -351,7 +351,7 @@ class Sniffer:
 
         rdr = reader(StringIO(sample), self.sniff(sample))
 
-        header = rdr.next() # assume first row is header
+        header = next(rdr) # assume first row is header
 
         columns = len(header)
         columnTypes = {}
diff --git a/Lib/difflib.py b/Lib/difflib.py
index 2dca7495d5..2a057d91c3 100644
--- a/Lib/difflib.py
+++ b/Lib/difflib.py
@@ -1430,7 +1430,7 @@ def _mdiff(fromlines, tolines, context=None, linejunk=None,
             # so we can do some very readable comparisons.
             while len(lines) < 4:
                 try:
-                    lines.append(diff_lines_iterator.next())
+                    lines.append(next(diff_lines_iterator))
                 except StopIteration:
                     lines.append('X')
             s = ''.join([line[0] for line in lines])
@@ -1517,7 +1517,7 @@ def _mdiff(fromlines, tolines, context=None, linejunk=None,
         while True:
             # Collecting lines of text until we have a from/to pair
             while (len(fromlines)==0 or len(tolines)==0):
-                from_line, to_line, found_diff =line_iterator.next()
+                from_line, to_line, found_diff = next(line_iterator)
                 if from_line is not None:
                     fromlines.append((from_line,found_diff))
                 if to_line is not None:
@@ -1532,7 +1532,7 @@ def _mdiff(fromlines, tolines, context=None, linejunk=None,
     line_pair_iterator = _line_pair_iterator()
     if context is None:
         while True:
-            yield line_pair_iterator.next()
+            yield next(line_pair_iterator)
     # Handle case where user wants context differencing.  We must do some
     # storage of lines until we know for sure that they are to be yielded.
     else:
@@ -1545,7 +1545,7 @@ def _mdiff(fromlines, tolines, context=None, linejunk=None,
             index, contextLines = 0, [None]*(context)
             found_diff = False
             while(found_diff is False):
-                from_line, to_line, found_diff = line_pair_iterator.next()
+                from_line, to_line, found_diff = next(line_pair_iterator)
                 i = index % context
                 contextLines[i] = (from_line, to_line, found_diff)
                 index += 1
@@ -1565,7 +1565,7 @@ def _mdiff(fromlines, tolines, context=None, linejunk=None,
             # Now yield the context lines after the change
             lines_to_write = context-1
             while(lines_to_write):
-                from_line, to_line, found_diff = line_pair_iterator.next()
+                from_line, to_line, found_diff = next(line_pair_iterator)
                 # If another change within the context, extend the context
                 if found_diff:
                     lines_to_write = context-1
diff --git a/Lib/email/feedparser.py b/Lib/email/feedparser.py
index afb02b32b2..9ed8e4d385 100644
--- a/Lib/email/feedparser.py
+++ b/Lib/email/feedparser.py
@@ -122,7 +122,7 @@ class BufferedSubFile(object):
     def __iter__(self):
         return self
 
-    def next(self):
+    def __next__(self):
         line = self.readline()
         if line == '':
             raise StopIteration
@@ -138,7 +138,7 @@ class FeedParser:
         self._factory = _factory
         self._input = BufferedSubFile()
         self._msgstack = []
-        self._parse = self._parsegen().next
+        self._parse = self._parsegen().__next__
         self._cur = None
         self._last = None
         self._headersonly = False
diff --git a/Lib/fileinput.py b/Lib/fileinput.py
index f6913eb8cb..b8b98706a3 100644
--- a/Lib/fileinput.py
+++ b/Lib/fileinput.py
@@ -240,7 +240,7 @@ class FileInput:
     def __iter__(self):
         return self
 
-    def next(self):
+    def __next__(self):
         try:
             line = self._buffer[self._bufindex]
         except IndexError:
@@ -259,7 +259,7 @@ class FileInput:
         if i != self._lineno:
             raise RuntimeError, "accessing lines out of order"
         try:
-            return self.next()
+            return self.__next__()
         except StopIteration:
             raise IndexError, "end of input reached"
 
diff --git a/Lib/gzip.py b/Lib/gzip.py
index 4ff4883ce7..fd72b9eb2a 100644
--- a/Lib/gzip.py
+++ b/Lib/gzip.py
@@ -453,7 +453,7 @@ class GzipFile:
     def __iter__(self):
         return self
 
-    def next(self):
+    def __next__(self):
         line = self.readline()
         if line:
             return line
diff --git a/Lib/heapq.py b/Lib/heapq.py
index 01680651fc..6ee26d17f9 100644
--- a/Lib/heapq.py
+++ b/Lib/heapq.py
@@ -325,7 +325,7 @@ def merge(*iterables):
     h_append = h.append
     for itnum, it in enumerate(map(iter, iterables)):
         try:
-            next = it.next
+            next = it.__next__
             h_append([next(), itnum, next])
         except _StopIteration:
             pass
diff --git a/Lib/hotshot/log.py b/Lib/hotshot/log.py
index 059142eec1..880b25c5ed 100644
--- a/Lib/hotshot/log.py
+++ b/Lib/hotshot/log.py
@@ -29,7 +29,7 @@ class LogReader:
         self._funcmap = {}
 
         self._reader = _hotshot.logreader(logfn)
-        self._nextitem = self._reader.next
+        self._nextitem = self._reader.__next__
         self._info = self._reader.info
         if 'current-directory' in self._info:
             self.cwd = self._info['current-directory']
@@ -93,7 +93,7 @@ class LogReader:
     # same bound method can be used as the __getitem__() method -- this
     # avoids using an additional method call which kills the performance.
 
-    def next(self, index=0):
+    def __next__(self, index=0):
         while 1:
             # This call may raise StopIteration:
             what, tdelta, fileno, lineno = self._nextitem()
diff --git a/Lib/httplib.py b/Lib/httplib.py
index 8876aadd8f..89d5392252 100644
--- a/Lib/httplib.py
+++ b/Lib/httplib.py
@@ -1098,7 +1098,7 @@ class SSLFile(SharedSocketClient):
     def __iter__(self):
         return self
 
-    def next(self):
+    def __next__(self):
         line = self.readline()
         if not line:
             raise StopIteration
diff --git a/Lib/inspect.py b/Lib/inspect.py
index d4cfc0714a..0be0419719 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -603,7 +603,7 @@ def getblock(lines):
     """Extract the block of code at the top of the given list of lines."""
     blockfinder = BlockFinder()
     try:
-        tokenize.tokenize(iter(lines).next, blockfinder.tokeneater)
+        tokenize.tokenize(iter(lines).__next__, blockfinder.tokeneater)
     except (EndOfBlock, IndentationError):
         pass
     return lines[:blockfinder.last]
diff --git a/Lib/io.py b/Lib/io.py
index 6bda7e52f7..2b85da72cf 100644
--- a/Lib/io.py
+++ b/Lib/io.py
@@ -904,7 +904,7 @@ class TextIOBase(IOBase):
         """
         return self
 
-    def next(self) -> str:
+    def __next__(self) -> str:
         """Same as readline() except raises StopIteration on immediate EOF."""
         line = self.readline()
         if not line:
@@ -1125,7 +1125,7 @@ class TextIOWrapper(TextIOBase):
             self._pending = res[n:]
             return self._simplify(res[:n])
 
-    def next(self) -> str:
+    def __next__(self) -> str:
         self._telling = False
         line = self.readline()
         if not line:
diff --git a/Lib/mailbox.py b/Lib/mailbox.py
index fde71327b9..9642d83c96 100755
--- a/Lib/mailbox.py
+++ b/Lib/mailbox.py
@@ -480,7 +480,7 @@ class Maildir(Mailbox):
             self._onetime_keys = iter(self.keys())
         while True:
             try:
-                return self[self._onetime_keys.next()]
+                return self[next(self._onetime_keys)]
             except StopIteration:
                 return None
             except KeyError:
diff --git a/Lib/pickle.py b/Lib/pickle.py
index 8e772e7704..2b01b02ed2 100644
--- a/Lib/pickle.py
+++ b/Lib/pickle.py
@@ -640,7 +640,7 @@ class Pickler:
             tmp = []
             for i in r:
                 try:
-                    x = items.next()
+                    x = next(items)
                     tmp.append(x)
                 except StopIteration:
                     items = None
@@ -688,7 +688,7 @@ class Pickler:
             tmp = []
             for i in r:
                 try:
-                    tmp.append(items.next())
+                    tmp.append(next(items))
                 except StopIteration:
                     items = None
                     break
diff --git a/Lib/pstats.py b/Lib/pstats.py
index 87038d9c21..59c84fe983 100644
--- a/Lib/pstats.py
+++ b/Lib/pstats.py
@@ -396,7 +396,7 @@ class Stats:
         subheader = False
         for cc, nc, tt, ct, callers in self.stats.values():
             if callers:
-                value = iter(callers.values()).next()
+                value = next(iter(callers.values()))
                 subheader = isinstance(value, tuple)
                 break
         if subheader:
diff --git a/Lib/pyclbr.py b/Lib/pyclbr.py
index fdbfbd46cc..c402a0994a 100644
--- a/Lib/pyclbr.py
+++ b/Lib/pyclbr.py
@@ -161,7 +161,7 @@ def _readmodule(module, path, inpackage=None):
                 # close previous nested classes and defs
                 while stack and stack[-1][1] >= thisindent:
                     del stack[-1]
-                tokentype, meth_name, start, end, line = g.next()
+                tokentype, meth_name, start, end, line = next(g)
                 if tokentype != NAME:
                     continue # Syntax error
                 if stack:
@@ -179,11 +179,11 @@ def _readmodule(module, path, inpackage=None):
                 # close previous nested classes and defs
                 while stack and stack[-1][1] >= thisindent:
                     del stack[-1]
-                tokentype, class_name, start, end, line = g.next()
+                tokentype, class_name, start, end, line = next(g)
                 if tokentype != NAME:
                     continue # Syntax error
                 # parse what follows the class name
-                tokentype, token, start, end, line = g.next()
+                tokentype, token, start, end, line = next(g)
                 inherit = None
                 if token == '(':
                     names = [] # List of superclasses
@@ -191,7 +191,7 @@ def _readmodule(module, path, inpackage=None):
                     level = 1
                     super = [] # Tokens making up current superclass
                     while True:
-                        tokentype, token, start, end, line = g.next()
+                        tokentype, token, start, end, line = next(g)
                         if token in (')', ',') and level == 1:
                             n = "".join(super)
                             if n in dict:
@@ -287,7 +287,7 @@ def _getnamelist(g):
             name2 = None
         names.append((name, name2))
         while token != "," and "\n" not in token:
-            tokentype, token, start, end, line = g.next()
+            tokentype, token, start, end, line = next(g)
         if token != ",":
             break
     return names
@@ -297,15 +297,15 @@ def _getname(g):
     # name is the dotted name, or None if there was no dotted name,
     # and token is the next input token.
     parts = []
-    tokentype, token, start, end, line = g.next()
+    tokentype, token, start, end, line = next(g)
     if tokentype != NAME and token != '*':
         return (None, token)
     parts.append(token)
     while True:
-        tokentype, token, start, end, line = g.next()
+        tokentype, token, start, end, line = next(g)
         if token != '.':
             break
-        tokentype, token, start, end, line = g.next()
+        tokentype, token, start, end, line = next(g)
         if tokentype != NAME:
             break
         parts.append(token)
diff --git a/Lib/shelve.py b/Lib/shelve.py
index d86718e141..697ae4f0f9 100644
--- a/Lib/shelve.py
+++ b/Lib/shelve.py
@@ -174,7 +174,7 @@ class BsdDbShelf(Shelf):
         return (key, Unpickler(f).load())
 
     def next(self):
-        (key, value) = self.dict.next()
+        (key, value) = next(self.dict)
         f = StringIO(value)
         return (key, Unpickler(f).load())
 
diff --git a/Lib/shlex.py b/Lib/shlex.py
index d81e99ec84..520b637bcb 100644
--- a/Lib/shlex.py
+++ b/Lib/shlex.py
@@ -265,7 +265,7 @@ class shlex:
     def __iter__(self):
         return self
 
-    def next(self):
+    def __next__(self):
         token = self.get_token()
         if token == self.eof:
             raise StopIteration
diff --git a/Lib/socket.py b/Lib/socket.py
index 2222600721..3fe6ec5c53 100644
--- a/Lib/socket.py
+++ b/Lib/socket.py
@@ -409,7 +409,7 @@ class _fileobject(object):
     def __iter__(self):
         return self
 
-    def next(self):
+    def __next__(self):
         line = self.readline()
         if not line:
             raise StopIteration
diff --git a/Lib/sqlite3/test/dbapi.py b/Lib/sqlite3/test/dbapi.py
index 287848a438..5a97acfb2c 100644
--- a/Lib/sqlite3/test/dbapi.py
+++ b/Lib/sqlite3/test/dbapi.py
@@ -286,7 +286,7 @@ class CursorTests(unittest.TestCase):
             def __init__(self):
                 self.value = 5
 
-            def next(self):
+            def __next__(self):
                 if self.value == 10:
                     raise StopIteration
                 else:
diff --git a/Lib/tarfile.py b/Lib/tarfile.py
index 146bbb717b..963127c2b3 100644
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -2046,7 +2046,7 @@ class TarIter:
         """Return iterator object.
         """
         return self
-    def next(self):
+    def __next__(self):
         """Return the next item using TarFile's next() method.
            When all members have been read, set TarFile as _loaded.
         """
diff --git a/Lib/tempfile.py b/Lib/tempfile.py
index f4f10581bd..0ebf6b4fc5 100644
--- a/Lib/tempfile.py
+++ b/Lib/tempfile.py
@@ -124,7 +124,7 @@ class _RandomNameSequence:
     def __iter__(self):
         return self
 
-    def next(self):
+    def __next__(self):
         m = self.mutex
         c = self.characters
         choose = self.rng.choice
@@ -191,7 +191,7 @@ def _get_default_tempdir():
             dir = _os.path.normcase(_os.path.abspath(dir))
         # Try only a few names per directory.
         for seq in xrange(100):
-            name = namer.next()
+            name = next(namer)
             filename = _os.path.join(dir, name)
             try:
                 fd = _os.open(filename, flags, 0600)
@@ -230,7 +230,7 @@ def _mkstemp_inner(dir, pre, suf, flags):
     names = _get_candidate_names()
 
     for seq in xrange(TMP_MAX):
-        name = names.next()
+        name = next(names)
         file = _os.path.join(dir, pre + name + suf)
         try:
             fd = _os.open(file, flags, 0600)
@@ -322,7 +322,7 @@ def mkdtemp(suffix="", prefix=template, dir=None):
     names = _get_candidate_names()
 
     for seq in xrange(TMP_MAX):
-        name = names.next()
+        name = next(names)
         file = _os.path.join(dir, prefix + name + suffix)
         try:
             _os.mkdir(file, 0700)
@@ -357,7 +357,7 @@ def mktemp(suffix="", prefix=template, dir=None):
 
     names = _get_candidate_names()
     for seq in xrange(TMP_MAX):
-        name = names.next()
+        name = next(names)
         file = _os.path.join(dir, prefix + name + suffix)
         if not _exists(file):
             return file
diff --git a/Lib/test/list_tests.py b/Lib/test/list_tests.py
index a6180811b1..ad1052365e 100644
--- a/Lib/test/list_tests.py
+++ b/Lib/test/list_tests.py
@@ -77,7 +77,7 @@ class CommonTest(seq_tests.CommonTest):
         a = self.type2test(range(20))
         r = reversed(a)
         self.assertEqual(list(r), self.type2test(range(19, -1, -1)))
-        self.assertRaises(StopIteration, r.next)
+        self.assertRaises(StopIteration, next, r)
         self.assertEqual(list(reversed(self.type2test())),
                          self.type2test())
 
diff --git a/Lib/test/mapping_tests.py b/Lib/test/mapping_tests.py
index 77d66b2062..d595cc5ec4 100644
--- a/Lib/test/mapping_tests.py
+++ b/Lib/test/mapping_tests.py
@@ -69,7 +69,7 @@ class BasicTestMappingProtocol(unittest.TestCase):
         if not d: self.fail("Full mapping must compare to True")
         # keys(), items(), iterkeys() ...
         def check_iterandlist(iter, lst, ref):
-            self.assert_(hasattr(iter, 'next'))
+            self.assert_(hasattr(iter, '__next__'))
             self.assert_(hasattr(iter, '__iter__'))
             x = list(iter)
             self.assert_(set(x)==set(lst)==set(ref))
@@ -81,8 +81,8 @@ class BasicTestMappingProtocol(unittest.TestCase):
         check_iterandlist(iter(d.items()), list(d.items()),
                           self.reference.items())
         #get
-        key, value = iter(d.items()).next()
-        knownkey, knownvalue = iter(self.other.items()).next()
+        key, value = next(iter(d.items()))
+        knownkey, knownvalue = next(iter(self.other.items()))
         self.assertEqual(d.get(key, knownvalue), value)
         self.assertEqual(d.get(knownkey, knownvalue), knownvalue)
         self.failIf(knownkey in d)
@@ -107,8 +107,8 @@ class BasicTestMappingProtocol(unittest.TestCase):
         self.assertEqual(dict(p), self.reference)
         d = self._full_mapping(self.reference)
         #setdefault
-        key, value = iter(d.items()).next()
-        knownkey, knownvalue = iter(self.other.items()).next()
+        key, value = next(iter(d.items()))
+        knownkey, knownvalue = next(iter(self.other.items()))
         self.assertEqual(d.setdefault(key, knownvalue), value)
         self.assertEqual(d[key], value)
         self.assertEqual(d.setdefault(knownkey, knownvalue), knownvalue)
@@ -225,7 +225,7 @@ class BasicTestMappingProtocol(unittest.TestCase):
                         self.i = 1
                     def __iter__(self):
                         return self
-                    def next(self):
+                    def __next__(self):
                         if self.i:
                             self.i = 0
                             return 'a'
@@ -242,7 +242,7 @@ class BasicTestMappingProtocol(unittest.TestCase):
                         self.i = ord('a')
                     def __iter__(self):
                         return self
-                    def next(self):
+                    def __next__(self):
                         if self.i <= ord('z'):
                             rtn = chr(self.i)
                             self.i += 1
@@ -257,7 +257,7 @@ class BasicTestMappingProtocol(unittest.TestCase):
         class badseq(object):
             def __iter__(self):
                 return self
-            def next(self):
+            def __next__(self):
                 raise Exc()
 
         self.assertRaises(Exc, d.update, badseq())
@@ -456,7 +456,7 @@ class TestMappingProtocol(BasicTestMappingProtocol):
         class BadSeq(object):
             def __iter__(self):
                 return self
-            def next(self):
+            def __next__(self):
                 raise Exc()
 
         self.assertRaises(Exc, self.type2test.fromkeys, BadSeq())
diff --git a/Lib/test/seq_tests.py b/Lib/test/seq_tests.py
index 0dfe7e4aab..d4e72e146e 100644
--- a/Lib/test/seq_tests.py
+++ b/Lib/test/seq_tests.py
@@ -26,7 +26,7 @@ class IterFunc:
         self.i = 0
     def __iter__(self):
         return self
-    def next(self):
+    def __next__(self):
         if self.i >= len(self.seqn): raise StopIteration
         v = self.seqn[self.i]
         self.i += 1
@@ -46,14 +46,14 @@ class IterNextOnly:
     def __init__(self, seqn):
         self.seqn = seqn
         self.i = 0
-    def next(self):
+    def __next__(self):
         if self.i >= len(self.seqn): raise StopIteration
         v = self.seqn[self.i]
         self.i += 1
         return v
 
 class IterNoNext:
-    'Iterator missing next()'
+    'Iterator missing __next__()'
     def __init__(self, seqn):
         self.seqn = seqn
         self.i = 0
@@ -67,7 +67,7 @@ class IterGenExc:
         self.i = 0
     def __iter__(self):
         return self
-    def next(self):
+    def __next__(self):
         3 // 0
 
 class IterFuncStop:
@@ -76,7 +76,7 @@ class IterFuncStop:
         pass
     def __iter__(self):
         return self
-    def next(self):
+    def __next__(self):
         raise StopIteration
 
 from itertools import chain, imap
@@ -296,7 +296,7 @@ class CommonTest(unittest.TestCase):
         class T(self.type2test):
             def __getitem__(self, key):
                 return str(key) + '!!!'
-        self.assertEqual(iter(T((1,2))).next(), 1)
+        self.assertEqual(next(iter(T((1,2)))), 1)
 
     def test_repeat(self):
         for m in xrange(4):
diff --git a/Lib/test/test_StringIO.py b/Lib/test/test_StringIO.py
index 9f79b02e16..83cd76c0d1 100644
--- a/Lib/test/test_StringIO.py
+++ b/Lib/test/test_StringIO.py
@@ -89,14 +89,14 @@ class TestGenericStringIO(unittest.TestCase):
         eq(iter(self._fp), self._fp)
         # Does this object support the iteration protocol?
         unless(hasattr(self._fp, '__iter__'))
-        unless(hasattr(self._fp, 'next'))
+        unless(hasattr(self._fp, '__next__'))
         i = 0
         for line in self._fp:
             eq(line, self._line + '\n')
             i += 1
         eq(i, 5)
         self._fp.close()
-        self.assertRaises(ValueError, self._fp.next)
+        self.assertRaises(ValueError, next, self._fp)
 
 class TestStringIO(TestGenericStringIO):
     MODULE = StringIO
diff --git a/Lib/test/test_bsddb.py b/Lib/test/test_bsddb.py
index 3a62f9c1c7..876a1000dd 100755
--- a/Lib/test/test_bsddb.py
+++ b/Lib/test/test_bsddb.py
@@ -72,7 +72,7 @@ class TestBSDDB(unittest.TestCase):
         di = iter(self.d)
         while 1:
             try:
-                key = di.next()
+                key = next(di)
                 self.d[key] = 'modified '+key
             except StopIteration:
                 break
@@ -83,7 +83,7 @@ class TestBSDDB(unittest.TestCase):
         fi = iter(self.f)
         while 1:
             try:
-                key = fi.next()
+                key = next(fi)
                 self.f[key] = 'modified '+key
             except StopIteration:
                 break
@@ -97,7 +97,7 @@ class TestBSDDB(unittest.TestCase):
         di = iter(self.d.items())
         while 1:
             try:
-                k, v = di.next()
+                k, v = next(di)
                 self.d[k] = 'modified '+v
             except StopIteration:
                 break
@@ -108,7 +108,7 @@ class TestBSDDB(unittest.TestCase):
         fi = iter(self.f.items())
         while 1:
             try:
-                k, v = fi.next()
+                k, v = next(fi)
                 self.f[k] = 'modified '+v
             except StopIteration:
                 break
@@ -160,13 +160,13 @@ class TestBSDDB(unittest.TestCase):
         if hasattr(self.f, 'iteritems'):
             if debug: print("D")
             i = iter(self.f.items())
-            k,v = i.next()
+            k,v = next(i)
             if debug: print("E")
             self.f[k] = "please don't deadlock"
             if debug: print("F")
             while 1:
                 try:
-                    k,v = i.next()
+                    k,v = next(i)
                 except StopIteration:
                     break
             if debug: print("F2")
@@ -176,7 +176,7 @@ class TestBSDDB(unittest.TestCase):
             while i:
                 try:
                     if debug: print("H")
-                    k = i.next()
+                    k = next(i)
                     if debug: print("I")
                     self.f[k] = "deadlocks-r-us"
                     if debug: print("J")
@@ -201,7 +201,7 @@ class TestBSDDB(unittest.TestCase):
         i = iter(self.f.iteritems())
         nc2 = len(self.f._cursor_refs)
         # use the iterator (should run to the first yield, creating the cursor)
-        k, v = i.next()
+        k, v = next(i)
         nc3 = len(self.f._cursor_refs)
         # destroy the iterator; this should cause the weakref callback
         # to remove the cursor object from self.f._cursor_refs
diff --git a/Lib/test/test_builtin.py b/Lib/test/test_builtin.py
index 05e80e4580..500516cefb 100644
--- a/Lib/test/test_builtin.py
+++ b/Lib/test/test_builtin.py
@@ -907,9 +907,9 @@ class BuiltinTest(unittest.TestCase):
             lists.append(unicode("12"))
         for l in lists:
             i = iter(l)
-            self.assertEqual(i.next(), '1')
-            self.assertEqual(i.next(), '2')
-            self.assertRaises(StopIteration, i.next)
+            self.assertEqual(next(i), '1')
+            self.assertEqual(next(i), '2')
+            self.assertRaises(StopIteration, next, i)
 
     def test_isinstance(self):
         class C:
@@ -1305,6 +1305,33 @@ class BuiltinTest(unittest.TestCase):
         self.assertEqual(min(data, key=f),
                          sorted(data, key=f)[0])
 
+    def test_next(self):
+        it = iter(range(2))
+        self.assertEqual(next(it), 0)
+        self.assertEqual(next(it), 1)
+        self.assertRaises(StopIteration, next, it)
+        self.assertRaises(StopIteration, next, it)
+        self.assertEquals(next(it, 42), 42)
+
+        class Iter(object):
+            def __iter__(self):
+                return self
+            def __next__(self):
+                raise StopIteration
+
+        it = iter(Iter())
+        self.assertEquals(next(it, 42), 42)
+        self.assertRaises(StopIteration, next, it)
+
+        def gen():
+            yield 1
+            return
+
+        it = gen()
+        self.assertEquals(next(it), 1)
+        self.assertRaises(StopIteration, next, it)
+        self.assertEquals(next(it, 42), 42)
+
     def test_oct(self):
         self.assertEqual(oct(100), '0144')
         self.assertEqual(oct(100), '0144')
diff --git a/Lib/test/test_csv.py b/Lib/test/test_csv.py
index 2cdc807444..980f3fc855 100644
--- a/Lib/test/test_csv.py
+++ b/Lib/test/test_csv.py
@@ -271,13 +271,13 @@ class Test_Csv(unittest.TestCase):
     def test_read_linenum(self):
         r = csv.reader(['line,1', 'line,2', 'line,3'])
         self.assertEqual(r.line_num, 0)
-        r.next()
+        next(r)
         self.assertEqual(r.line_num, 1)
-        r.next()
+        next(r)
         self.assertEqual(r.line_num, 2)
-        r.next()
+        next(r)
         self.assertEqual(r.line_num, 3)
-        self.assertRaises(StopIteration, r.next)
+        self.assertRaises(StopIteration, next, r)
         self.assertEqual(r.line_num, 3)
 
 class TestDialectRegistry(unittest.TestCase):
@@ -338,9 +338,9 @@ class TestDialectRegistry(unittest.TestCase):
         try:
             fileobj.write("abc def\nc1ccccc1 benzene\n")
             fileobj.seek(0)
-            rdr = csv.reader(fileobj, dialect=space())
-            self.assertEqual(rdr.next(), ["abc", "def"])
-            self.assertEqual(rdr.next(), ["c1ccccc1", "benzene"])
+            reader = csv.reader(fileobj, dialect=space())
+            self.assertEqual(next(reader), ["abc", "def"])
+            self.assertEqual(next(reader), ["c1ccccc1", "benzene"])
         finally:
             fileobj.close()
             os.unlink(name)
@@ -593,7 +593,7 @@ class TestDictFields(unittest.TestCase):
             fileobj.seek(0)
             reader = csv.DictReader(fileobj,
                                     fieldnames=["f1", "f2", "f3"])
-            self.assertEqual(reader.next(), {"f1": '1', "f2": '2', "f3": 'abc'})
+            self.assertEqual(next(reader), {"f1": '1', "f2": '2', "f3": 'abc'})
         finally:
             fileobj.close()
             os.unlink(name)
@@ -605,7 +605,7 @@ class TestDictFields(unittest.TestCase):
             fileobj.write("f1,f2,f3\r\n1,2,abc\r\n")
             fileobj.seek(0)
             reader = csv.DictReader(fileobj)
-            self.assertEqual(reader.next(), {"f1": '1', "f2": '2', "f3": 'abc'})
+            self.assertEqual(next(reader), {"f1": '1', "f2": '2', "f3": 'abc'})
         finally:
             fileobj.close()
             os.unlink(name)
@@ -618,7 +618,7 @@ class TestDictFields(unittest.TestCase):
             fileobj.seek(0)
             reader = csv.DictReader(fileobj,
                                     fieldnames=["f1", "f2"])
-            self.assertEqual(reader.next(), {"f1": '1', "f2": '2',
+            self.assertEqual(next(reader), {"f1": '1', "f2": '2',
                                              None: ["abc", "4", "5", "6"]})
         finally:
             fileobj.close()
@@ -632,7 +632,7 @@ class TestDictFields(unittest.TestCase):
             fileobj.seek(0)
             reader = csv.DictReader(fileobj,
                                     fieldnames=["f1", "f2"], restkey="_rest")
-            self.assertEqual(reader.next(), {"f1": '1', "f2": '2',
+            self.assertEqual(next(reader), {"f1": '1', "f2": '2',
                                              "_rest": ["abc", "4", "5", "6"]})
         finally:
             fileobj.close()
@@ -645,7 +645,7 @@ class TestDictFields(unittest.TestCase):
             fileobj.write("f1,f2\r\n1,2,abc,4,5,6\r\n")
             fileobj.seek(0)
             reader = csv.DictReader(fileobj, restkey="_rest")
-            self.assertEqual(reader.next(), {"f1": '1', "f2": '2',
+            self.assertEqual(next(reader), {"f1": '1', "f2": '2',
                                              "_rest": ["abc", "4", "5", "6"]})
         finally:
             fileobj.close()
@@ -660,9 +660,9 @@ class TestDictFields(unittest.TestCase):
             reader = csv.DictReader(fileobj,
                                     fieldnames="1 2 3 4 5 6".split(),
                                     restval="DEFAULT")
-            self.assertEqual(reader.next(), {"1": '1', "2": '2', "3": 'abc',
+            self.assertEqual(next(reader), {"1": '1', "2": '2', "3": 'abc',
                                              "4": '4', "5": '5', "6": '6'})
-            self.assertEqual(reader.next(), {"1": '1', "2": '2', "3": 'abc',
+            self.assertEqual(next(reader), {"1": '1', "2": '2', "3": 'abc',
                                              "4": 'DEFAULT', "5": 'DEFAULT',
                                              "6": 'DEFAULT'})
         finally:
@@ -678,7 +678,7 @@ class TestDictFields(unittest.TestCase):
 
         reader = csv.DictReader(sample,
                                 fieldnames="i1 float i2 s1 s2".split())
-        self.assertEqual(reader.next(), {"i1": '2147483648',
+        self.assertEqual(next(reader), {"i1": '2147483648',
                                          "float": '43.0e12',
                                          "i2": '17',
                                          "s1": 'abc',
@@ -688,16 +688,16 @@ class TestDictFields(unittest.TestCase):
         reader = csv.DictReader(["1,2,abc,4,5,6\r\n","\r\n",
                                  "1,2,abc,4,5,6\r\n"],
                                 fieldnames="1 2 3 4 5 6".split())
-        self.assertEqual(reader.next(), {"1": '1', "2": '2', "3": 'abc',
+        self.assertEqual(next(reader), {"1": '1', "2": '2', "3": 'abc',
                                          "4": '4', "5": '5', "6": '6'})
-        self.assertEqual(reader.next(), {"1": '1', "2": '2', "3": 'abc',
+        self.assertEqual(next(reader), {"1": '1', "2": '2', "3": 'abc',
                                          "4": '4', "5": '5', "6": '6'})
 
     def test_read_semi_sep(self):
         reader = csv.DictReader(["1;2;abc;4;5;6\r\n"],
                                 fieldnames="1 2 3 4 5 6".split(),
                                 delimiter=';')
-        self.assertEqual(reader.next(), {"1": '1', "2": '2', "3": 'abc',
+        self.assertEqual(next(reader), {"1": '1', "2": '2', "3": 'abc',
                                          "4": '4', "5": '5', "6": '6'})
 
 class TestArrayWrites(unittest.TestCase):
diff --git a/Lib/test/test_deque.py b/Lib/test/test_deque.py
index 28099045a6..7df31b7035 100644
--- a/Lib/test/test_deque.py
+++ b/Lib/test/test_deque.py
@@ -394,13 +394,13 @@ class TestVariousIteratorArgs(unittest.TestCase):
         d = deque('abcdefg')
         it = iter(d)
         d.pop()
-        self.assertRaises(RuntimeError, it.next)
+        self.assertRaises(RuntimeError, next, it)
 
     def test_runtime_error_on_empty_deque(self):
         d = deque()
         it = iter(d)
         d.append(10)
-        self.assertRaises(RuntimeError, it.next)
+        self.assertRaises(RuntimeError, next, it)
 
 class Deque(deque):
     pass
@@ -567,7 +567,7 @@ deque(['a', 'b', 'd', 'e', 'f'])
 ...     while pending:
 ...         task = pending.popleft()
 ...         try:
-...             yield task.next()
+...             yield next(task)
 ...         except StopIteration:
 ...             continue
 ...         pending.append(task)
diff --git a/Lib/test/test_dict.py b/Lib/test/test_dict.py
index 679181fc25..d8dfd7e413 100644
--- a/Lib/test/test_dict.py
+++ b/Lib/test/test_dict.py
@@ -144,7 +144,7 @@ class DictTest(unittest.TestCase):
                         self.i = 1
                     def __iter__(self):
                         return self
-                    def next(self):
+                    def __next__(self):
                         if self.i:
                             self.i = 0
                             return 'a'
@@ -161,7 +161,7 @@ class DictTest(unittest.TestCase):
                         self.i = ord('a')
                     def __iter__(self):
                         return self
-                    def next(self):
+                    def __next__(self):
                         if self.i <= ord('z'):
                             rtn = chr(self.i)
                             self.i += 1
@@ -175,7 +175,7 @@ class DictTest(unittest.TestCase):
         class badseq(object):
             def __iter__(self):
                 return self
-            def next(self):
+            def __next__(self):
                 raise Exc()
 
         self.assertRaises(Exc, {}.update, badseq())
@@ -225,7 +225,7 @@ class DictTest(unittest.TestCase):
         class BadSeq(object):
             def __iter__(self):
                 return self
-            def next(self):
+            def __next__(self):
                 raise Exc()
 
         self.assertRaises(Exc, dict.fromkeys, BadSeq())
diff --git a/Lib/test/test_difflib.py b/Lib/test/test_difflib.py
index 83fad1548d..b5168dd709 100644
--- a/Lib/test/test_difflib.py
+++ b/Lib/test/test_difflib.py
@@ -16,9 +16,9 @@ class TestSFbugs(unittest.TestCase):
     def test_comparing_empty_lists(self):
         # Check fix for bug #979794
         group_gen = difflib.SequenceMatcher(None, [], []).get_grouped_opcodes()
-        self.assertRaises(StopIteration, group_gen.next)
+        self.assertRaises(StopIteration, next, group_gen)
         diff_gen = difflib.unified_diff([], [])
-        self.assertRaises(StopIteration, diff_gen.next)
+        self.assertRaises(StopIteration, next, diff_gen)
 
 patch914575_from1 = """
    1. Beautiful is beTTer than ugly.
diff --git a/Lib/test/test_enumerate.py b/Lib/test/test_enumerate.py
index 6290070460..af7512d215 100644
--- a/Lib/test/test_enumerate.py
+++ b/Lib/test/test_enumerate.py
@@ -17,7 +17,7 @@ class I:
         self.i = 0
     def __iter__(self):
         return self
-    def next(self):
+    def __next__(self):
         if self.i >= len(self.seqn): raise StopIteration
         v = self.seqn[self.i]
         self.i += 1
@@ -37,7 +37,7 @@ class X:
     def __init__(self, seqn):
         self.seqn = seqn
         self.i = 0
-    def next(self):
+    def __next__(self):
         if self.i >= len(self.seqn): raise StopIteration
         v = self.seqn[self.i]
         self.i += 1
@@ -50,11 +50,11 @@ class E:
         self.i = 0
     def __iter__(self):
         return self
-    def next(self):
+    def __next__(self):
         3 // 0
 
 class N:
-    'Iterator missing next()'
+    'Iterator missing __next__()'
     def __init__(self, seqn):
         self.seqn = seqn
         self.i = 0
@@ -76,17 +76,17 @@ class EnumerateTestCase(unittest.TestCase):
     def test_getitemseqn(self):
         self.assertEqual(list(self.enum(G(self.seq))), self.res)
         e = self.enum(G(''))
-        self.assertRaises(StopIteration, e.next)
+        self.assertRaises(StopIteration, next, e)
 
     def test_iteratorseqn(self):
         self.assertEqual(list(self.enum(I(self.seq))), self.res)
         e = self.enum(I(''))
-        self.assertRaises(StopIteration, e.next)
+        self.assertRaises(StopIteration, next, e)
 
     def test_iteratorgenerator(self):
         self.assertEqual(list(self.enum(Ig(self.seq))), self.res)
         e = self.enum(Ig(''))
-        self.assertRaises(StopIteration, e.next)
+        self.assertRaises(StopIteration, next, e)
 
     def test_noniterable(self):
         self.assertRaises(TypeError, self.enum, X(self.seq))
diff --git a/Lib/test/test_extcall.py b/Lib/test/test_extcall.py
index 453f464a99..552583201c 100644
--- a/Lib/test/test_extcall.py
+++ b/Lib/test/test_extcall.py
@@ -103,7 +103,7 @@ class Nothing:
         self.c = 0
     def __iter__(self):
         return self
-    def next(self):
+    def __next__(self):
         if self.c == 4:
             raise StopIteration
         c = self.c
diff --git a/Lib/test/test_file.py b/Lib/test/test_file.py
index c4bd610d3e..f682f8950a 100644
--- a/Lib/test/test_file.py
+++ b/Lib/test/test_file.py
@@ -95,7 +95,7 @@ class AutoFileTests(unittest.TestCase):
         self.assert_(f.closed)
 
     def testMethods(self):
-        methods = ['fileno', 'flush', 'isatty', 'next', 'read', 'readinto',
+        methods = ['fileno', 'flush', 'isatty', '__next__', 'read', 'readinto',
                    'readline', 'readlines', 'seek', 'tell', 'truncate',
                    'write', '__iter__']
         if sys.platform.startswith('atheos'):
@@ -248,7 +248,7 @@ class OtherFileTests(unittest.TestCase):
             # Test for appropriate errors mixing read* and iteration
             for methodname, args in methods:
                 f = open(TESTFN, 'rb')
-                if f.next() != filler:
+                if next(f) != filler:
                     self.fail, "Broken testfile"
                 meth = getattr(f, methodname)
                 try:
@@ -269,7 +269,7 @@ class OtherFileTests(unittest.TestCase):
             # between 4 and 16384 (inclusive).
             f = open(TESTFN, 'rb')
             for i in range(nchunks):
-                f.next()
+                next(f)
             testline = testlines.pop(0)
             try:
                 line = f.readline()
diff --git a/Lib/test/test_fileinput.py b/Lib/test/test_fileinput.py
index b7f84c686a..17ca944d71 100644
--- a/Lib/test/test_fileinput.py
+++ b/Lib/test/test_fileinput.py
@@ -179,7 +179,7 @@ try:
     t2 = writeTmp(2, ["C\nD"])
     fi = FileInput(files=(t1, t2))
     verify(fi.fileno() == -1)
-    line = fi.next()
+    line = next(fi)
     verify(fi.fileno() != -1)
     fi.nextfile()
     verify(fi.fileno() == -1)
diff --git a/Lib/test/test_generators.py b/Lib/test/test_generators.py
index 12276be0d9..08d354a13c 100644
--- a/Lib/test/test_generators.py
+++ b/Lib/test/test_generators.py
@@ -10,14 +10,14 @@ Let's try a simple generator:
     1
     2
     >>> g = f()
-    >>> g.next()
+    >>> next(g)
     1
-    >>> g.next()
+    >>> next(g)
     2
 
 "Falling off the end" stops the generator:
 
-    >>> g.next()
+    >>> next(g)
     Traceback (most recent call last):
       File "<stdin>", line 1, in ?
       File "<stdin>", line 2, in g
@@ -31,14 +31,14 @@ Let's try a simple generator:
     ...     yield 2 # never reached
     ...
     >>> g = f()
-    >>> g.next()
+    >>> next(g)
     1
-    >>> g.next()
+    >>> next(g)
     Traceback (most recent call last):
       File "<stdin>", line 1, in ?
       File "<stdin>", line 3, in f
     StopIteration
-    >>> g.next() # once stopped, can't be resumed
+    >>> next(g) # once stopped, can't be resumed
     Traceback (most recent call last):
       File "<stdin>", line 1, in ?
     StopIteration
@@ -51,13 +51,13 @@ Let's try a simple generator:
     ...     yield 2 # never reached
     ...
     >>> g = f()
-    >>> g.next()
+    >>> next(g)
     1
-    >>> g.next()
+    >>> next(g)
     Traceback (most recent call last):
       File "<stdin>", line 1, in ?
     StopIteration
-    >>> g.next()
+    >>> next(g)
     Traceback (most recent call last):
       File "<stdin>", line 1, in ?
     StopIteration
@@ -105,7 +105,7 @@ Generators always return to the most recent caller:
 
     >>> def creator():
     ...     r = yrange(5)
-    ...     print("creator", r.next())
+    ...     print("creator", next(r))
     ...     return r
     ...
     >>> def caller():
@@ -141,10 +141,10 @@ Specification:  Yield
     running:
 
     >>> def g():
-    ...     i = me.next()
+    ...     i = next(me)
     ...     yield i
     >>> me = g()
-    >>> me.next()
+    >>> next(me)
     Traceback (most recent call last):
      ...
       File "<string>", line 2, in g
@@ -185,13 +185,13 @@ Specification: Generators and Exception Propagation
     ...     yield f()  # the zero division exception propagates
     ...     yield 42   # and we'll never get here
     >>> k = g()
-    >>> k.next()
+    >>> next(k)
     Traceback (most recent call last):
       File "<stdin>", line 1, in ?
       File "<stdin>", line 2, in g
       File "<stdin>", line 2, in f
     ZeroDivisionError: integer division or modulo by zero
-    >>> k.next()  # and the generator cannot be resumed
+    >>> next(k)  # and the generator cannot be resumed
     Traceback (most recent call last):
       File "<stdin>", line 1, in ?
     StopIteration
@@ -382,9 +382,9 @@ From the Iterators list, about the types of these things.
 >>> type(i)
 <type 'generator'>
 >>> [s for s in dir(i) if not s.startswith('_')]
-['close', 'gi_frame', 'gi_running', 'next', 'send', 'throw']
->>> print(i.next.__doc__)
-x.next() -> the next value, or raise StopIteration
+['close', 'gi_frame', 'gi_running', 'send', 'throw']
+>>> print(i.__next__.__doc__)
+x.__next__() <==> next(x)
 >>> iter(i) is i
 True
 >>> import types
@@ -406,7 +406,7 @@ AttributeError: readonly attribute
 >>> me = g()
 >>> me.gi_running
 0
->>> me.next()
+>>> next(me)
 1
 >>> me.gi_running
 0
@@ -429,7 +429,7 @@ Subject: Re: PEP 255: Simple Generators
 ...             yield x
 ...
 ...     def find(self):
-...         return self.generator.next()
+...         return next(self.generator)
 ...
 ...     def union(self, parent):
 ...         if self.parent:
@@ -493,7 +493,7 @@ fun_tests = """
 Build up to a recursive Sieve of Eratosthenes generator.
 
 >>> def firstn(g, n):
-...     return [g.next() for i in range(n)]
+...     return [next(g) for i in range(n)]
 
 >>> def intsfrom(i):
 ...     while 1:
@@ -512,7 +512,7 @@ Build up to a recursive Sieve of Eratosthenes generator.
 [1, 2, 4, 5, 7, 8]
 
 >>> def sieve(ints):
-...     prime = ints.next()
+...     prime = next(ints)
 ...     yield prime
 ...     not_divisible_by_prime = exclude_multiples(prime, ints)
 ...     for p in sieve(not_divisible_by_prime):
@@ -536,19 +536,19 @@ Try writing it without generators, and correctly, and without generating
 [10, 20, 30, 40, 50, 60, 70, 80, 90, 100]
 
 >>> def merge(g, h):
-...     ng = g.next()
-...     nh = h.next()
+...     ng = next(g)
+...     nh = next(h)
 ...     while 1:
 ...         if ng < nh:
 ...             yield ng
-...             ng = g.next()
+...             ng = next(g)
 ...         elif ng > nh:
 ...             yield nh
-...             nh = h.next()
+...             nh = next(h)
 ...         else:
 ...             yield ng
-...             ng = g.next()
-...             nh = h.next()
+...             ng = next(g)
+...             nh = next(h)
 
 The following works, but is doing a whale of a lot of redundant work --
 it's not clear how to get the internal uses of m235 to share a single
@@ -589,7 +589,7 @@ arguments are iterable -- a LazyList is the same as a generator to times().
 >>> class LazyList:
 ...     def __init__(self, g):
 ...         self.sofar = []
-...         self.fetch = g.next
+...         self.fetch = g.__next__
 ...
 ...     def __getitem__(self, i):
 ...         sofar, fetch = self.sofar, self.fetch
@@ -626,10 +626,10 @@ Ye olde Fibonacci generator, LazyList style.
 ...
 ...     def sum(g, h):
 ...         while 1:
-...             yield g.next() + h.next()
+...             yield next(g) + next(h)
 ...
 ...     def tail(g):
-...         g.next()    # throw first away
+...         next(g)    # throw first away
 ...         for x in g:
 ...             yield x
 ...
@@ -705,12 +705,12 @@ Ye olde Fibonacci generator, tee style.
 ...
 ...     def _isum(g, h):
 ...         while 1:
-...             yield g.next() + h.next()
+...             yield next(g) + next(h)
 ...
 ...     def _fib():
 ...         yield 1
 ...         yield 2
-...         fibTail.next() # throw first away
+...         next(fibTail) # throw first away
 ...         for res in _isum(fibHead, fibTail):
 ...             yield res
 ...
@@ -890,13 +890,13 @@ This one caused a crash (see SF bug 567538):
 ...             yield i
 ...
 >>> g = f()
->>> print(g.next())
+>>> print(next(g))
 0
->>> print(g.next())
+>>> print(next(g))
 1
->>> print(g.next())
+>>> print(next(g))
 2
->>> print(g.next())
+>>> print(next(g))
 Traceback (most recent call last):
 StopIteration
 """
@@ -1013,7 +1013,7 @@ def flat_conjoin(gs):  # rename to conjoin to run tests with this instead
         # Descend.
         try:
             while i < n:
-                it = iters[i] = gs[i]().next
+                it = iters[i] = gs[i]().__next__
                 values[i] = it()
                 i += 1
         except _StopIteration:
@@ -1463,7 +1463,7 @@ Sending a value into a started generator:
 ...     print((yield 1))
 ...     yield 2
 >>> g = f()
->>> g.next()
+>>> next(g)
 1
 >>> g.send(42)
 42
@@ -1506,7 +1506,7 @@ A yield expression with augmented assignment.
 ...         seq.append(count)
 >>> seq = []
 >>> c = coroutine(seq)
->>> c.next()
+>>> next(c)
 >>> print(seq)
 []
 >>> c.send(10)
@@ -1558,7 +1558,7 @@ Now check some throw() conditions:
 ...             print("caught ValueError (%s)" % (v))
 >>> import sys
 >>> g = f()
->>> g.next()
+>>> next(g)
 
 >>> g.throw(ValueError) # type only
 caught ValueError ()
@@ -1642,7 +1642,7 @@ Now let's try closing a generator:
 ...         print("exiting")
 
 >>> g = f()
->>> g.next()
+>>> next(g)
 >>> g.close()
 exiting
 >>> g.close()  # should be no-op now
@@ -1652,7 +1652,7 @@ exiting
 >>> def f(): yield      # an even simpler generator
 >>> f().close()         # close before opening
 >>> g = f()
->>> g.next()
+>>> next(g)
 >>> g.close()           # close normally
 
 And finalization:
@@ -1663,7 +1663,7 @@ And finalization:
 ...         print("exiting")
 
 >>> g = f()
->>> g.next()
+>>> next(g)
 >>> del g
 exiting
 
@@ -1675,7 +1675,7 @@ Now let's try some ill-behaved generators:
 ...     except GeneratorExit:
 ...         yield "foo!"
 >>> g = f()
->>> g.next()
+>>> next(g)
 >>> g.close()
 Traceback (most recent call last):
   ...
@@ -1688,7 +1688,7 @@ Our ill-behaved code should be invoked during GC:
 >>> import sys, StringIO
 >>> old, sys.stderr = sys.stderr, StringIO.StringIO()
 >>> g = f()
->>> g.next()
+>>> next(g)
 >>> del g
 >>> sys.stderr.getvalue().startswith(
 ...     "Exception RuntimeError: 'generator ignored GeneratorExit' in "
@@ -1704,7 +1704,7 @@ And errors thrown during closing should propagate:
 ...     except GeneratorExit:
 ...         raise TypeError("fie!")
 >>> g = f()
->>> g.next()
+>>> next(g)
 >>> g.close()
 Traceback (most recent call last):
   ...
@@ -1760,7 +1760,7 @@ would trigger if it starts being uncleanable again.
 ...     class gen:
 ...         def __iter__(self):
 ...             return self
-...         def next(self):
+...         def __next__(self):
 ...             return self.item
 ...     g = gen()
 ...     head, tail = itertools.tee(g)
@@ -1771,7 +1771,7 @@ would trigger if it starts being uncleanable again.
 Make sure to also test the involvement of the tee-internal teedataobject,
 which stores returned items.
 
->>> item = it.next()
+>>> item = next(it)
 
 
 
diff --git a/Lib/test/test_genexps.py b/Lib/test/test_genexps.py
index 1b24672900..cafca57234 100644
--- a/Lib/test/test_genexps.py
+++ b/Lib/test/test_genexps.py
@@ -34,24 +34,24 @@ Test first class
 Test direct calls to next()
 
     >>> g = (i*i for i in range(3))
-    >>> g.next()
+    >>> next(g)
     0
-    >>> g.next()
+    >>> next(g)
     1
-    >>> g.next()
+    >>> next(g)
     4
-    >>> g.next()
+    >>> next(g)
     Traceback (most recent call last):
       File "<pyshell#21>", line 1, in -toplevel-
-        g.next()
+        next(g)
     StopIteration
 
 Does it stay stopped?
 
-    >>> g.next()
+    >>> next(g)
     Traceback (most recent call last):
       File "<pyshell#21>", line 1, in -toplevel-
-        g.next()
+        next(g)
     StopIteration
     >>> list(g)
     []
@@ -157,7 +157,7 @@ Generators always return to the most recent caller:
 
     >>> def creator():
     ...     r = yrange(5)
-    ...     print("creator", r.next())
+    ...     print("creator", next(r))
     ...     return r
     >>> def caller():
     ...     r = creator()
@@ -181,32 +181,32 @@ Generators can call other generators:
 
 Verify that a gen exp cannot be resumed while it is actively running:
 
-    >>> g = (me.next() for i in xrange(10))
+    >>> g = (next(me) for i in xrange(10))
     >>> me = g
-    >>> me.next()
+    >>> next(me)
     Traceback (most recent call last):
       File "<pyshell#30>", line 1, in -toplevel-
-        me.next()
+        next(me)
       File "<pyshell#28>", line 1, in <generator expression>
-        g = (me.next() for i in xrange(10))
+        g = (next(me) for i in xrange(10))
     ValueError: generator already executing
 
 Verify exception propagation
 
     >>> g = (10 // i for i in (5, 0, 2))
-    >>> g.next()
+    >>> next(g)
     2
-    >>> g.next()
+    >>> next(g)
     Traceback (most recent call last):
       File "<pyshell#37>", line 1, in -toplevel-
-        g.next()
+        next(g)
       File "<pyshell#35>", line 1, in <generator expression>
         g = (10 // i for i in (5, 0, 2))
     ZeroDivisionError: integer division or modulo by zero
-    >>> g.next()
+    >>> next(g)
     Traceback (most recent call last):
       File "<pyshell#38>", line 1, in -toplevel-
-        g.next()
+        next(g)
     StopIteration
 
 Make sure that None is a valid return value
@@ -217,12 +217,12 @@ Make sure that None is a valid return value
 Check that generator attributes are present
 
     >>> g = (i*i for i in range(3))
-    >>> expected = set(['gi_frame', 'gi_running', 'next'])
+    >>> expected = set(['gi_frame', 'gi_running'])
     >>> set(attr for attr in dir(g) if not attr.startswith('__')) >= expected
     True
 
-    >>> print(g.next.__doc__)
-    x.next() -> the next value, or raise StopIteration
+    >>> print(g.__next__.__doc__)
+    x.__next__() <==> next(x)
     >>> import types
     >>> isinstance(g, types.GeneratorType)
     True
@@ -238,7 +238,7 @@ Verify that the running flag is set properly
     >>> me = g
     >>> me.gi_running
     0
-    >>> me.next()
+    >>> next(me)
     1
     >>> me.gi_running
     0
diff --git a/Lib/test/test_grammar.py b/Lib/test/test_grammar.py
index 2c1b6ca941..bd04735dab 100644
--- a/Lib/test/test_grammar.py
+++ b/Lib/test/test_grammar.py
@@ -785,9 +785,9 @@ class GrammarTests(unittest.TestCase):
     def testGenexps(self):
         # generator expression tests
         g = ([x for x in range(10)] for x in range(1))
-        self.assertEqual(g.next(), [x for x in range(10)])
+        self.assertEqual(next(g), [x for x in range(10)])
         try:
-            g.next()
+            next(g)
             self.fail('should produce StopIteration exception')
         except StopIteration:
             pass
@@ -795,7 +795,7 @@ class GrammarTests(unittest.TestCase):
         a = 1
         try:
             g = (a for d in a)
-            g.next()
+            next(g)
             self.fail('should produce TypeError')
         except TypeError:
             pass
diff --git a/Lib/test/test_heapq.py b/Lib/test/test_heapq.py
index 156c835151..dbbfcb0f6d 100644
--- a/Lib/test/test_heapq.py
+++ b/Lib/test/test_heapq.py
@@ -180,7 +180,7 @@ class I:
         self.i = 0
     def __iter__(self):
         return self
-    def next(self):
+    def __next__(self):
         if self.i >= len(self.seqn): raise StopIteration
         v = self.seqn[self.i]
         self.i += 1
@@ -200,14 +200,14 @@ class X:
     def __init__(self, seqn):
         self.seqn = seqn
         self.i = 0
-    def next(self):
+    def __next__(self):
         if self.i >= len(self.seqn): raise StopIteration
         v = self.seqn[self.i]
         self.i += 1
         return v
 
 class N:
-    'Iterator missing next()'
+    'Iterator missing __next__()'
     def __init__(self, seqn):
         self.seqn = seqn
         self.i = 0
@@ -221,7 +221,7 @@ class E:
         self.i = 0
     def __iter__(self):
         return self
-    def next(self):
+    def __next__(self):
         3 // 0
 
 class S:
@@ -230,7 +230,7 @@ class S:
         pass
     def __iter__(self):
         return self
-    def next(self):
+    def __next__(self):
         raise StopIteration
 
 from itertools import chain, imap
diff --git a/Lib/test/test_iter.py b/Lib/test/test_iter.py
index 820911da35..65e143d10b 100644
--- a/Lib/test/test_iter.py
+++ b/Lib/test/test_iter.py
@@ -22,7 +22,7 @@ class BasicIterClass:
     def __init__(self, n):
         self.n = n
         self.i = 0
-    def next(self):
+    def __next__(self):
         res = self.i
         if res >= self.n:
             raise StopIteration
@@ -53,7 +53,7 @@ class TestCase(unittest.TestCase):
         res = []
         while 1:
             try:
-                val = it.next()
+                val = next(it)
             except StopIteration:
                 break
             res.append(val)
@@ -342,7 +342,7 @@ class TestCase(unittest.TestCase):
                         self.i = 0
                     def __iter__(self):
                         return self
-                    def next(self):
+                    def __next__(self):
                         i = self.i
                         self.i = i + 1
                         if i < len(self.vals):
@@ -447,7 +447,7 @@ class TestCase(unittest.TestCase):
             def __iter__(self):
                 return self
 
-            def next(self):
+            def __next__(self):
                 i = self.i
                 self.i = i+1
                 return i
@@ -514,12 +514,12 @@ class TestCase(unittest.TestCase):
             def __iter__(self):
                 return self
 
-            def next(self):
+            def __next__(self):
                 i = self.i
                 self.i = i+1
                 if i == 2:
                     return unicode("fooled you!")
-                return self.it.next()
+                return next(self.it)
 
         f = open(TESTFN, "w")
         try:
@@ -682,7 +682,7 @@ class TestCase(unittest.TestCase):
                     self.finish = finish
                     self.i = self.start
 
-                def next(self):
+                def __next__(self):
                     if self.i >= self.finish:
                         raise StopIteration
                     result = str(self.i) + '\n'
diff --git a/Lib/test/test_iterlen.py b/Lib/test/test_iterlen.py
index 8ff1d6bb17..28f25676e2 100644
--- a/Lib/test/test_iterlen.py
+++ b/Lib/test/test_iterlen.py
@@ -10,7 +10,7 @@ The desired invariant is:  len(it)==len(list(it)).
 A complication is that an iterable and iterator can be the same object. To
 maintain the invariant, an iterator needs to dynamically update its length.
 For instance, an iterable such as xrange(10) always reports its length as ten,
-but it=iter(xrange(10)) starts at ten, and then goes to nine after it.next().
+but it=iter(xrange(10)) starts at ten, and then goes to nine after next(it).
 Having this capability means that map() can ignore the distinction between
 map(func, iterable) and map(func, iter(iterable)).
 
@@ -67,9 +67,9 @@ class TestInvariantWithoutMutations(unittest.TestCase):
         it = self.it
         for i in reversed(xrange(1, n+1)):
             self.assertEqual(len(it), i)
-            it.next()
+            next(it)
         self.assertEqual(len(it), 0)
-        self.assertRaises(StopIteration, it.next)
+        self.assertRaises(StopIteration, next, it)
         self.assertEqual(len(it), 0)
 
 class TestTemporarilyImmutable(TestInvariantWithoutMutations):
@@ -80,10 +80,10 @@ class TestTemporarilyImmutable(TestInvariantWithoutMutations):
 
         it = self.it
         self.assertEqual(len(it), n)
-        it.next()
+        next(it)
         self.assertEqual(len(it), n-1)
         self.mutate()
-        self.assertRaises(RuntimeError, it.next)
+        self.assertRaises(RuntimeError, next, it)
         self.assertEqual(len(it), 0)
 
 ## ------- Concrete Type Tests -------
@@ -166,8 +166,8 @@ class TestList(TestInvariantWithoutMutations):
     def test_mutation(self):
         d = range(n)
         it = iter(d)
-        it.next()
-        it.next()
+        next(it)
+        next(it)
         self.assertEqual(len(it), n-2)
         d.append(n)
         self.assertEqual(len(it), n-1)  # grow with append
@@ -185,8 +185,8 @@ class TestListReversed(TestInvariantWithoutMutations):
     def test_mutation(self):
         d = range(n)
         it = reversed(d)
-        it.next()
-        it.next()
+        next(it)
+        next(it)
         self.assertEqual(len(it), n-2)
         d.append(n)
         self.assertEqual(len(it), n-2)  # ignore append
@@ -204,8 +204,8 @@ class TestSeqIter(TestInvariantWithoutMutations):
     def test_mutation(self):
         d = UserList(range(n))
         it = iter(d)
-        it.next()
-        it.next()
+        next(it)
+        next(it)
         self.assertEqual(len(it), n-2)
         d.append(n)
         self.assertEqual(len(it), n-1)  # grow with append
@@ -223,8 +223,8 @@ class TestSeqIterReversed(TestInvariantWithoutMutations):
     def test_mutation(self):
         d = UserList(range(n))
         it = reversed(d)
-        it.next()
-        it.next()
+        next(it)
+        next(it)
         self.assertEqual(len(it), n-2)
         d.append(n)
         self.assertEqual(len(it), n-2)  # ignore append
diff --git a/Lib/test/test_itertools.py b/Lib/test/test_itertools.py
index bbebbd9558..d74b9d5c48 100644
--- a/Lib/test/test_itertools.py
+++ b/Lib/test/test_itertools.py
@@ -34,7 +34,7 @@ class StopNow:
     'Class emulating an empty iterable.'
     def __iter__(self):
         return self
-    def next(self):
+    def __next__(self):
         raise StopIteration
 
 def take(n, seq):
@@ -58,12 +58,12 @@ class TestBasicOps(unittest.TestCase):
         self.assertRaises(OverflowError, list, islice(count(sys.maxint-5), 10))
         c = count(3)
         self.assertEqual(repr(c), 'count(3)')
-        c.next()
+        next(c)
         self.assertEqual(repr(c), 'count(4)')
         c = count(-9)
         self.assertEqual(repr(c), 'count(-9)')
-        c.next()
-        self.assertEqual(c.next(), -8)
+        next(c)
+        self.assertEqual(next(c), -8)
 
     def test_cycle(self):
         self.assertEqual(take(10, cycle('abc')), list('abcabcabca'))
@@ -121,7 +121,7 @@ class TestBasicOps(unittest.TestCase):
         r = sorted([(len(list(g)) , k) for k, g in groupby(sorted(s))], reverse=True)[:3]
         self.assertEqual(r, [(5, 'a'), (2, 'r'), (2, 'b')])
 
-        # iter.next failure
+        # iter.__next__ failure
         class ExpectedError(Exception):
             pass
         def delayed_raise(n=0):
@@ -131,9 +131,9 @@ class TestBasicOps(unittest.TestCase):
         def gulp(iterable, keyp=None, func=list):
             return [func(g) for k, g in groupby(iterable, keyp)]
 
-        # iter.next failure on outer object
+        # iter.__next__ failure on outer object
         self.assertRaises(ExpectedError, gulp, delayed_raise(0))
-        # iter.next failure on inner object
+        # iter.__next__ failure on inner object
         self.assertRaises(ExpectedError, gulp, delayed_raise(1))
 
         # __cmp__ failure
@@ -169,7 +169,7 @@ class TestBasicOps(unittest.TestCase):
         self.assertRaises(TypeError, ifilter, lambda x:x)
         self.assertRaises(TypeError, ifilter, lambda x:x, range(6), 7)
         self.assertRaises(TypeError, ifilter, isEven, 3)
-        self.assertRaises(TypeError, ifilter(range(6), range(6)).next)
+        self.assertRaises(TypeError, next, ifilter(range(6), range(6)))
 
     def test_ifilterfalse(self):
         self.assertEqual(list(ifilterfalse(isEven, range(6))), [1,3,5])
@@ -179,7 +179,7 @@ class TestBasicOps(unittest.TestCase):
         self.assertRaises(TypeError, ifilterfalse, lambda x:x)
         self.assertRaises(TypeError, ifilterfalse, lambda x:x, range(6), 7)
         self.assertRaises(TypeError, ifilterfalse, isEven, 3)
-        self.assertRaises(TypeError, ifilterfalse(range(6), range(6)).next)
+        self.assertRaises(TypeError, next, ifilterfalse(range(6), range(6)))
 
     def test_izip(self):
         # XXX This is rather silly now that builtin zip() calls izip()...
@@ -276,9 +276,9 @@ class TestBasicOps(unittest.TestCase):
         self.assertEqual(list(imap(operator.pow, [])), [])
         self.assertRaises(TypeError, imap)
         self.assertRaises(TypeError, imap, operator.neg)
-        self.assertRaises(TypeError, imap(10, range(5)).next)
-        self.assertRaises(ValueError, imap(errfunc, [4], [5]).next)
-        self.assertRaises(TypeError, imap(onearg, [4], [5]).next)
+        self.assertRaises(TypeError, next, imap(10, range(5)))
+        self.assertRaises(ValueError, next, imap(errfunc, [4], [5]))
+        self.assertRaises(TypeError, next, imap(onearg, [4], [5]))
 
     def test_starmap(self):
         self.assertEqual(list(starmap(operator.pow, zip(range(3), range(1,7)))),
@@ -289,9 +289,9 @@ class TestBasicOps(unittest.TestCase):
         self.assertRaises(TypeError, list, starmap(operator.pow, [[4,5]]))
         self.assertRaises(TypeError, starmap)
         self.assertRaises(TypeError, starmap, operator.pow, [(4,5)], 'extra')
-        self.assertRaises(TypeError, starmap(10, [(4,5)]).next)
-        self.assertRaises(ValueError, starmap(errfunc, [(4,5)]).next)
-        self.assertRaises(TypeError, starmap(onearg, [(4,5)]).next)
+        self.assertRaises(TypeError, next, starmap(10, [(4,5)]))
+        self.assertRaises(ValueError, next, starmap(errfunc, [(4,5)]))
+        self.assertRaises(TypeError, next, starmap(onearg, [(4,5)]))
 
     def test_islice(self):
         for args in [          # islice(args) should agree with range(args)
@@ -344,11 +344,11 @@ class TestBasicOps(unittest.TestCase):
         self.assertRaises(TypeError, takewhile)
         self.assertRaises(TypeError, takewhile, operator.pow)
         self.assertRaises(TypeError, takewhile, operator.pow, [(4,5)], 'extra')
-        self.assertRaises(TypeError, takewhile(10, [(4,5)]).next)
-        self.assertRaises(ValueError, takewhile(errfunc, [(4,5)]).next)
+        self.assertRaises(TypeError, next, takewhile(10, [(4,5)]))
+        self.assertRaises(ValueError, next, takewhile(errfunc, [(4,5)]))
         t = takewhile(bool, [1, 1, 1, 0, 0, 0])
         self.assertEqual(list(t), [1, 1, 1])
-        self.assertRaises(StopIteration, t.next)
+        self.assertRaises(StopIteration, next, t)
 
     def test_dropwhile(self):
         data = [1, 3, 5, 20, 2, 4, 6, 8]
@@ -358,8 +358,8 @@ class TestBasicOps(unittest.TestCase):
         self.assertRaises(TypeError, dropwhile)
         self.assertRaises(TypeError, dropwhile, operator.pow)
         self.assertRaises(TypeError, dropwhile, operator.pow, [(4,5)], 'extra')
-        self.assertRaises(TypeError, dropwhile(10, [(4,5)]).next)
-        self.assertRaises(ValueError, dropwhile(errfunc, [(4,5)]).next)
+        self.assertRaises(TypeError, next, dropwhile(10, [(4,5)]))
+        self.assertRaises(ValueError, next, dropwhile(errfunc, [(4,5)]))
 
     def test_tee(self):
         n = 200
@@ -380,13 +380,13 @@ class TestBasicOps(unittest.TestCase):
 
         a, b = tee(irange(n)) # test dealloc of leading iterator
         for i in xrange(100):
-            self.assertEqual(a.next(), i)
+            self.assertEqual(next(a), i)
         del a
         self.assertEqual(list(b), range(n))
 
         a, b = tee(irange(n)) # test dealloc of trailing iterator
         for i in xrange(100):
-            self.assertEqual(a.next(), i)
+            self.assertEqual(next(a), i)
         del b
         self.assertEqual(list(a), range(100, n))
 
@@ -396,7 +396,7 @@ class TestBasicOps(unittest.TestCase):
             lists = ([], [])
             its = tee(irange(n))
             for i in order:
-                value = its[i].next()
+                value = next(its[i])
                 lists[i].append(value)
             self.assertEqual(lists[0], range(n))
             self.assertEqual(lists[1], range(n))
@@ -415,9 +415,9 @@ class TestBasicOps(unittest.TestCase):
         # test long-lagged and multi-way split
         a, b, c = tee(xrange(2000), 3)
         for i in xrange(100):
-            self.assertEqual(a.next(), i)
+            self.assertEqual(next(a), i)
         self.assertEqual(list(b), range(2000))
-        self.assertEqual([c.next(), c.next()], range(2))
+        self.assertEqual([next(c), next(c)], range(2))
         self.assertEqual(list(a), range(100,2000))
         self.assertEqual(list(c), range(2,2000))
 
@@ -451,33 +451,33 @@ class TestBasicOps(unittest.TestCase):
         self.assertRaises(ReferenceError, getattr, p, '__class__')
 
     def test_StopIteration(self):
-        self.assertRaises(StopIteration, izip().next)
+        self.assertRaises(StopIteration, next, izip())
 
         for f in (chain, cycle, izip, groupby):
-            self.assertRaises(StopIteration, f([]).next)
-            self.assertRaises(StopIteration, f(StopNow()).next)
+            self.assertRaises(StopIteration, next, f([]))
+            self.assertRaises(StopIteration, next, f(StopNow()))
 
-        self.assertRaises(StopIteration, islice([], None).next)
-        self.assertRaises(StopIteration, islice(StopNow(), None).next)
+        self.assertRaises(StopIteration, next, islice([], None))
+        self.assertRaises(StopIteration, next, islice(StopNow(), None))
 
         p, q = tee([])
-        self.assertRaises(StopIteration, p.next)
-        self.assertRaises(StopIteration, q.next)
+        self.assertRaises(StopIteration, next, p)
+        self.assertRaises(StopIteration, next, q)
         p, q = tee(StopNow())
-        self.assertRaises(StopIteration, p.next)
-        self.assertRaises(StopIteration, q.next)
+        self.assertRaises(StopIteration, next, p)
+        self.assertRaises(StopIteration, next, q)
 
-        self.assertRaises(StopIteration, repeat(None, 0).next)
+        self.assertRaises(StopIteration, next, repeat(None, 0))
 
         for f in (ifilter, ifilterfalse, imap, takewhile, dropwhile, starmap):
-            self.assertRaises(StopIteration, f(lambda x:x, []).next)
-            self.assertRaises(StopIteration, f(lambda x:x, StopNow()).next)
+            self.assertRaises(StopIteration, next, f(lambda x:x, []))
+            self.assertRaises(StopIteration, next, f(lambda x:x, StopNow()))
 
 class TestGC(unittest.TestCase):
 
     def makecycle(self, iterator, container):
         container.append(iterator)
-        iterator.next()
+        next(iterator)
         del container, iterator
 
     def test_chain(self):
@@ -547,7 +547,7 @@ class I:
         self.i = 0
     def __iter__(self):
         return self
-    def next(self):
+    def __next__(self):
         if self.i >= len(self.seqn): raise StopIteration
         v = self.seqn[self.i]
         self.i += 1
@@ -567,14 +567,14 @@ class X:
     def __init__(self, seqn):
         self.seqn = seqn
         self.i = 0
-    def next(self):
+    def __next__(self):
         if self.i >= len(self.seqn): raise StopIteration
         v = self.seqn[self.i]
         self.i += 1
         return v
 
 class N:
-    'Iterator missing next()'
+    'Iterator missing __next__()'
     def __init__(self, seqn):
         self.seqn = seqn
         self.i = 0
@@ -588,7 +588,7 @@ class E:
         self.i = 0
     def __iter__(self):
         return self
-    def next(self):
+    def __next__(self):
         3 // 0
 
 class S:
@@ -597,7 +597,7 @@ class S:
         pass
     def __iter__(self):
         return self
-    def next(self):
+    def __next__(self):
         raise StopIteration
 
 def L(seqn):
@@ -748,13 +748,13 @@ class RegressionTests(unittest.TestCase):
             def g(value, first=[1]):
                 if first:
                     del first[:]
-                    f(z.next())
+                    f(next(z))
                 return value
             items = list(tuple2)
             items[1:1] = list(tuple1)
             gen = imap(g, items)
             z = izip(*[gen]*len(tuple1))
-            z.next()
+            next(z)
 
         def f(t):
             global T
@@ -930,7 +930,7 @@ Samuele
 ...     "s -> (s0,s1), (s1,s2), (s2, s3), ..."
 ...     a, b = tee(iterable)
 ...     try:
-...         b.next()
+...         next(b)
 ...     except StopIteration:
 ...         pass
 ...     return izip(a, b)
diff --git a/Lib/test/test_mailbox.py b/Lib/test/test_mailbox.py
index 803edd589d..8650cef710 100644
--- a/Lib/test/test_mailbox.py
+++ b/Lib/test/test_mailbox.py
@@ -1518,11 +1518,11 @@ class TestProxyFileBase(TestBase):
         # Iterate by line
         proxy.seek(0)
         iterator = iter(proxy)
-        self.assert_(iterator.next() == 'foo' + os.linesep)
-        self.assert_(iterator.next() == 'bar' + os.linesep)
-        self.assert_(iterator.next() == 'fred' + os.linesep)
-        self.assert_(iterator.next() == 'bob')
-        self.assertRaises(StopIteration, lambda: iterator.next())
+        self.assert_(next(iterator) == 'foo' + os.linesep)
+        self.assert_(next(iterator) == 'bar' + os.linesep)
+        self.assert_(next(iterator) == 'fred' + os.linesep)
+        self.assert_(next(iterator) == 'bob')
+        self.assertRaises(StopIteration, next, iterator)
 
     def _test_seek_and_tell(self, proxy):
         # Seek and use tell to check position
diff --git a/Lib/test/test_re.py b/Lib/test/test_re.py
index bb97433f40..bca2ecfd50 100644
--- a/Lib/test/test_re.py
+++ b/Lib/test/test_re.py
@@ -586,8 +586,8 @@ class ReTests(unittest.TestCase):
 
     def test_bug_581080(self):
         iter = re.finditer(r"\s", "a b")
-        self.assertEqual(iter.next().span(), (1,2))
-        self.assertRaises(StopIteration, iter.next)
+        self.assertEqual(next(iter).span(), (1,2))
+        self.assertRaises(StopIteration, next, iter)
 
         scanner = re.compile(r"\s").scanner("a b")
         self.assertEqual(scanner.search().span(), (1, 2))
@@ -595,9 +595,9 @@ class ReTests(unittest.TestCase):
 
     def test_bug_817234(self):
         iter = re.finditer(r".*", "asdf")
-        self.assertEqual(iter.next().span(), (0, 4))
-        self.assertEqual(iter.next().span(), (4, 4))
-        self.assertRaises(StopIteration, iter.next)
+        self.assertEqual(next(iter).span(), (0, 4))
+        self.assertEqual(next(iter).span(), (4, 4))
+        self.assertRaises(StopIteration, next, iter)
 
 
 def run_re_tests():
diff --git a/Lib/test/test_set.py b/Lib/test/test_set.py
index 8a43109f31..997e17f789 100644
--- a/Lib/test/test_set.py
+++ b/Lib/test/test_set.py
@@ -1382,7 +1382,7 @@ class I:
         self.i = 0
     def __iter__(self):
         return self
-    def next(self):
+    def __next__(self):
         if self.i >= len(self.seqn): raise StopIteration
         v = self.seqn[self.i]
         self.i += 1
@@ -1402,14 +1402,14 @@ class X:
     def __init__(self, seqn):
         self.seqn = seqn
         self.i = 0
-    def next(self):
+    def __next__(self):
         if self.i >= len(self.seqn): raise StopIteration
         v = self.seqn[self.i]
         self.i += 1
         return v
 
 class N:
-    'Iterator missing next()'
+    'Iterator missing __next__()'
     def __init__(self, seqn):
         self.seqn = seqn
         self.i = 0
@@ -1423,7 +1423,7 @@ class E:
         self.i = 0
     def __iter__(self):
         return self
-    def next(self):
+    def __next__(self):
         3 // 0
 
 class S:
@@ -1432,7 +1432,7 @@ class S:
         pass
     def __iter__(self):
         return self
-    def next(self):
+    def __next__(self):
         raise StopIteration
 
 from itertools import chain, imap
diff --git a/Lib/test/test_str.py b/Lib/test/test_str.py
index 226a16809e..0067bdbcfe 100644
--- a/Lib/test/test_str.py
+++ b/Lib/test/test_str.py
@@ -22,10 +22,10 @@ class StrTest(
     def test_iterators(self):
         # Make sure str objects have an __iter__ method
         it = "abc".__iter__()
-        self.assertEqual(it.next(), "a")
-        self.assertEqual(it.next(), "b")
-        self.assertEqual(it.next(), "c")
-        self.assertRaises(StopIteration, it.next)
+        self.assertEqual(next(it), "a")
+        self.assertEqual(next(it), "b")
+        self.assertEqual(next(it), "c")
+        self.assertRaises(StopIteration, next, it)
 
     def test_conversion(self):
         # Make sure __str__() behaves properly
diff --git a/Lib/test/test_tempfile.py b/Lib/test/test_tempfile.py
index 2047a6364e..a398d3740a 100644
--- a/Lib/test/test_tempfile.py
+++ b/Lib/test/test_tempfile.py
@@ -102,7 +102,7 @@ class test__RandomNameSequence(TC):
 
     def test_get_six_char_str(self):
         # _RandomNameSequence returns a six-character string
-        s = self.r.next()
+        s = next(self.r)
         self.nameCheck(s, '', '', '')
 
     def test_many(self):
@@ -111,7 +111,7 @@ class test__RandomNameSequence(TC):
         dict = {}
         r = self.r
         for i in xrange(TEST_FILES):
-            s = r.next()
+            s = next(r)
             self.nameCheck(s, '', '', '')
             self.failIf(s in dict)
             dict[s] = 1
diff --git a/Lib/test/test_tokenize.py b/Lib/test/test_tokenize.py
index d6c37775f0..0880f0f503 100644
--- a/Lib/test/test_tokenize.py
+++ b/Lib/test/test_tokenize.py
@@ -103,7 +103,7 @@ def test_roundtrip(f):
 
     t1 = [tok[:2] for tok in fulltok]
     newtext = untokenize(t1)
-    readline = iter(newtext.splitlines(1)).next
+    readline = iter(newtext.splitlines(1)).__next__
     t2 = [tok[:2] for tok in generate_tokens(readline)]
     if t1 != t2:
         raise TestFailed("untokenize() roundtrip failed for %r" % f)
@@ -224,7 +224,7 @@ def test_rarrow():
     This function exists solely to test the tokenization of the RARROW
     operator.
 
-    >>> tokenize(iter(['->']).next)   #doctest: +NORMALIZE_WHITESPACE
+    >>> tokenize(iter(['->']).__next__)   #doctest: +NORMALIZE_WHITESPACE
     1,0-1,2:\tOP\t'->'
     2,0-2,0:\tENDMARKER\t''
     """
diff --git a/Lib/test/test_unicode.py b/Lib/test/test_unicode.py
index b789fb0ba0..cb7586c2e9 100644
--- a/Lib/test/test_unicode.py
+++ b/Lib/test/test_unicode.py
@@ -99,10 +99,10 @@ class UnicodeTest(
     def test_iterators(self):
         # Make sure unicode objects have an __iter__ method
         it = u"\u1111\u2222\u3333".__iter__()
-        self.assertEqual(it.next(), u"\u1111")
-        self.assertEqual(it.next(), u"\u2222")
-        self.assertEqual(it.next(), u"\u3333")
-        self.assertRaises(StopIteration, it.next)
+        self.assertEqual(next(it), u"\u1111")
+        self.assertEqual(next(it), u"\u2222")
+        self.assertEqual(next(it), u"\u3333")
+        self.assertRaises(StopIteration, next, it)
 
     def test_count(self):
         string_tests.CommonTest.test_count(self)
diff --git a/Lib/test/test_userlist.py b/Lib/test/test_userlist.py
index 8c7ef2efe2..e9fbd2de13 100644
--- a/Lib/test/test_userlist.py
+++ b/Lib/test/test_userlist.py
@@ -51,7 +51,7 @@ class UserListTest(list_tests.CommonTest):
         class T(self.type2test):
             def __getitem__(self, key):
                 return str(key) + '!!!'
-        self.assertEqual(iter(T((1,2))).next(), "0!!!")
+        self.assertEqual(next(iter(T((1,2)))), "0!!!")
 
 def test_main():
     test_support.run_unittest(UserListTest)
diff --git a/Lib/test/test_wsgiref.py b/Lib/test/test_wsgiref.py
index f33c30dda4..d77e861dd6 100755
--- a/Lib/test/test_wsgiref.py
+++ b/Lib/test/test_wsgiref.py
@@ -108,13 +108,13 @@ def compare_generic_iter(make_it,match):
         it = make_it()
         if not iter(it) is it: raise AssertionError
         for item in match:
-            if not it.next()==item: raise AssertionError
+            if not next(it) == item: raise AssertionError
         try:
-            it.next()
+            next(it)
         except StopIteration:
             pass
         else:
-            raise AssertionError("Too many items from .next()",it)
+            raise AssertionError("Too many items from .__next__()", it)
 
 
 
diff --git a/Lib/tokenize.py b/Lib/tokenize.py
index 8dc4c53e91..1a72d6fc59 100644
--- a/Lib/tokenize.py
+++ b/Lib/tokenize.py
@@ -228,7 +228,7 @@ def untokenize(iterable):
         # Output text will tokenize the back to the input
         t1 = [tok[:2] for tok in generate_tokens(f.readline)]
         newcode = untokenize(t1)
-        readline = iter(newcode.splitlines(1)).next
+        readline = iter(newcode.splitlines(1)).__next__
         t2 = [tok[:2] for tokin generate_tokens(readline)]
         assert t1 == t2
     """
@@ -242,7 +242,7 @@ def generate_tokens(readline):
     readline() method of built-in file objects. Each call to the function
     should return one line of input as a string.  Alternately, readline
     can be a callable function terminating with StopIteration:
-        readline = open(myfile).next    # Example of alternate readline
+        readline = open(myfile).__next__    # Example of alternate readline
 
     The generator produces 5-tuples with these members: the token type; the
     token string; a 2-tuple (srow, scol) of ints specifying the row and
diff --git a/Lib/types.py b/Lib/types.py
index 9811646fc9..22d00f7784 100644
--- a/Lib/types.py
+++ b/Lib/types.py
@@ -7,7 +7,7 @@ import sys
 # Iterators in Python aren't a matter of type but of protocol.  A large
 # and changing number of builtin types implement *some* flavor of
 # iterator.  Don't check the type!  Use hasattr to check for both
-# "__iter__" and "next" attributes instead.
+# "__iter__" and "__next__" attributes instead.
 
 NoneType = type(None)
 TypeType = type
diff --git a/Lib/urllib.py b/Lib/urllib.py
index 60d2a413bf..4e24a8f051 100644
--- a/Lib/urllib.py
+++ b/Lib/urllib.py
@@ -902,8 +902,8 @@ class addbase:
             self.fileno = lambda: None
         if hasattr(self.fp, "__iter__"):
             self.__iter__ = self.fp.__iter__
-            if hasattr(self.fp, "next"):
-                self.next = self.fp.next
+            if hasattr(self.fp, "__next__"):
+                self.__next__ = self.fp.__next__
 
     def __repr__(self):
         return '<%s at %r whose fp = %r>' % (self.__class__.__name__,
diff --git a/Lib/wsgiref/util.py b/Lib/wsgiref/util.py
index 450a32fbce..5b44eda16d 100644
--- a/Lib/wsgiref/util.py
+++ b/Lib/wsgiref/util.py
@@ -26,7 +26,7 @@ class FileWrapper:
     def __iter__(self):
         return self
 
-    def next(self):
+    def __next__(self):
         data = self.filelike.read(self.blksize)
         if data:
             return data
diff --git a/Lib/wsgiref/validate.py b/Lib/wsgiref/validate.py
index 43784f9e66..09b0d950e2 100644
--- a/Lib/wsgiref/validate.py
+++ b/Lib/wsgiref/validate.py
@@ -98,7 +98,7 @@ Some of the things this checks:
   - That it is not a string (it should be a list of a single string; a
     string will work, but perform horribly).
 
-  - That .next() returns a string
+  - That .__next__() returns a string
 
   - That the iterator is not iterated over until start_response has
     been called (that can signal either a server or application
@@ -265,10 +265,10 @@ class IteratorWrapper:
     def __iter__(self):
         return self
 
-    def next(self):
+    def __next__(self):
         assert_(not self.closed,
             "Iterator read after closed")
-        v = self.iterator.next()
+        v = next(self.iterator)
         if self.check_start_response is not None:
             assert_(self.check_start_response,
                 "The application returns and we started iterating over its body, but start_response has not yet been called")
diff --git a/Lib/xml/dom/pulldom.py b/Lib/xml/dom/pulldom.py
index f0245c49c3..fe9a3a2196 100644
--- a/Lib/xml/dom/pulldom.py
+++ b/Lib/xml/dom/pulldom.py
@@ -228,7 +228,7 @@ class DOMEventStream:
             return rc
         raise IndexError
 
-    def next(self):
+    def __next__(self):
         rc = self.getEvent()
         if rc:
             return rc
diff --git a/Lib/xml/etree/ElementTree.py b/Lib/xml/etree/ElementTree.py
index 19bb74772b..694d6c4a90 100644
--- a/Lib/xml/etree/ElementTree.py
+++ b/Lib/xml/etree/ElementTree.py
@@ -893,7 +893,7 @@ class iterparse:
                     append((event, None))
                 parser.EndNamespaceDeclHandler = handler
 
-    def next(self):
+    def __next__(self):
         while 1:
             try:
                 item = self._events[self._index]
@@ -923,7 +923,7 @@ class iterparse:
             return self
     except NameError:
         def __getitem__(self, index):
-            return self.next()
+            return self.__next__()
 
 ##
 # Parses an XML document from a string constant.  This function can