add missing None check for send_activity in turn_context
@@ -149,7 +149,7 @@ class TurnContext(object):
result = await self._emit(self._on_send_activities, output, callback(self, output))
- return result[0] if len(result) > 0 else ResourceResponse()
+ return result[0] if result is not None and len(result) > 0 else ResourceResponse()
async def update_activity(self, activity: Activity):
"""
