libvirtaio: Fix compat with python 3.7

In python 3.7, async is now a keyword, so this throws a syntax error:

  File "/usr/lib64/python3.7/site-packages/libvirtaio.py", line 49
    from asyncio import async as ensure_future
                            ^
  SyntaxError: invalid syntax

Switch to getattr trickery to accomplish the same goal

Reviewed-by: Pavel Hrdina <phrdina@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
Signed-off-by: Cole Robinson <crobinso@redhat.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/libvirtaio.py b/libvirtaio.py
index 1c432dd..328e6f2 100644
--- a/libvirtaio.py
+++ b/libvirtaio.py
@@ -43,10 +43,13 @@ import warnings
 
 import libvirt
 
-try:
-    from asyncio import ensure_future
-except ImportError:
-    from asyncio import async as ensure_future
+# Python < 3.4.4 doesn't have 'ensure_future', so we have to fall
+# back to 'async'; however, since 'async' is a reserved keyword
+# in Python >= 3.7, we can't perform a straightforward import and
+# we have to resort to getattr() instead
+ensure_future = getattr(asyncio, "ensure_future", None)
+if not ensure_future:
+    ensure_future = getattr(asyncio, "async")
 
 
 class Callback(object):