Return to idle after complete

Author: Golf Player

nbclient/client.py

@@ -535,6 +535,7 @@ async def async_execute(self, reset_kc=False, **kwargs):
             self.nb.metadata['language_info'] = info_msg['content']['language_info']
             self.set_widgets_metadata()
         self._update_state(ExecutionState.COMPLETE)
+        self._update_state(ExecutionState.IDLE)
         return self.nb
 
     execute = run_sync(async_execute)