code: def _start_timers(self, peer_holdtime):
          
          neg_timer = min(self._holdtime, peer_holdtime)
          if neg_timer < self._holdtime:
              LOG.info('Negotiated hold time (%s) is lower then '
                       'configured/default (%s).', neg_timer, self._holdtime)
          # We use negotiated timer value.
          self._holdtime = neg_timer
          self._keepalive = self._create_timer('Keepalive Timer',
                                               self._send_keepalive)
          interval = self._holdtime // 3
          self._keepalive.start(interval, now=False)
          # Setup the expire timer.
          self._expiry = self._create_timer('Holdtime Timer', self._expired)
          self._expiry.start(self._holdtime, now=False)
          LOG.debug('Started keep-alive and expire timer for negotiated hold'
                    'time %s', self._holdtime)
docs: Starts keepalive and expire timers.
  
          Hold time is set to min. of peer and configured/default hold time.
          Starts keep alive timer and expire timer based on this value.