asyncio: Sync with upstream (compat module)
diff --git a/Lib/asyncio/selector_events.py b/Lib/asyncio/selector_events.py
index 7c5b9b5..4a99658 100644
--- a/Lib/asyncio/selector_events.py
+++ b/Lib/asyncio/selector_events.py
@@ -10,7 +10,6 @@
 import errno
 import functools
 import socket
-import sys
 import warnings
 try:
     import ssl
@@ -18,6 +17,7 @@
     ssl = None
 
 from . import base_events
+from . import compat
 from . import constants
 from . import events
 from . import futures
@@ -568,7 +568,7 @@
     # On Python 3.3 and older, objects with a destructor part of a reference
     # cycle are never destroyed. It's not more the case on Python 3.4 thanks
     # to the PEP 442.
-    if sys.version_info >= (3, 4):
+    if compat.PY34:
         def __del__(self):
             if self._sock is not None:
                 warnings.warn("unclosed transport %r" % self, ResourceWarning)