work around event loop limitation

Author: blink1073

jupyter_client/utils.py

@@ -13,8 +13,8 @@ def wrapped(*args, **kwargs):
         try:
             loop = asyncio.get_running_loop()
         except RuntimeError:
-            loop = asyncio.new_event_loop()
-            asyncio.set_event_loop(loop)
+            # Workaround for bugs.python.org/issue39529.
+            loop = asyncio.get_event_loop_policy().get_event_loop()
         import nest_asyncio  # type: ignore
 
         nest_asyncio.apply(loop)