code: def restore_event(self, requestId):
          
          with self.__requests:
              if requestId not in self.__requests:
                  self.__requests[requestId] = RequestEvent(requestId)
                  return True
          return False
docs: restore an event based on the requestId.
  
          For example if the user app had to shutdown with pending requests.
          The user can rebuild the Events they were waiting for based on the requestId(s).