code: def _handle_pong(self, ts, *args, **kwargs):
          
          log.info("BitfinexWSS.ping(): Ping received! (%ss)",
                   ts - self.ping_timer)
          self.ping_timer = None
docs: Handles pong messages; resets the self.ping_timer variable and logs
          info message.
          :param ts: timestamp, declares when data was received by the client
          :return: