Keep asyncio working with Python 3.3 too.

Author: gvanrossum

asyncio/selector_events.py

@@ -571,10 +571,15 @@ def __init__(self, loop, rawsock, protocol, sslcontext, waiter=None,
                 # context; in that case the sslcontext passed is None.
                 # The default is the same as used by urllib with
                 # cadefault=True.
-                sslcontext = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
-                sslcontext.options |= ssl.OP_NO_SSLv2
-                sslcontext.set_default_verify_paths()
-                sslcontext.verify_mode = ssl.CERT_REQUIRED
+                if hasattr(ssl, '_create_stdlib_context'):
+                    sslcontext = ssl._create_stdlib_context(
+                        cert_reqs=ssl.CERT_REQUIRED)
+                else:
+                    # Fallback for Python 3.3.
+                    sslcontext = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
+                    sslcontext.options |= ssl.OP_NO_SSLv2
+                    sslcontext.set_default_verify_paths()
+                    sslcontext.verify_mode = ssl.CERT_REQUIRED
 
         wrap_kwargs = {
             'server_side': server_side,