code: def _raise_or_append_exception(self):
          
          message = (
              'Connection dead, no heartbeat or data received in >= '
              '%ds' % (
                  self._interval * 2
              )
          )
          why = AMQPConnectionError(message)
          if self._exceptions is None:
              raise why
          self._exceptions.append(why)
docs: The connection is presumably dead and we need to raise or
          append an exception.
  
              If we have a list for exceptions, append the exception and let
              the connection handle it, if not raise the exception here.
  
          :return: