code: def _update_xmit_period(self):
          
          # RFC5880 Section 6.8.7.
          if self._desired_min_tx_interval > self._remote_min_rx_interval:
              xmit_period = self._desired_min_tx_interval
          else:
              xmit_period = self._remote_min_rx_interval
  
          # This updates the transmission period of BFD Control packets.
          # (RFC5880 Section 6.8.2 & 6.8.3.)
          if self._detect_mult == 1:
              xmit_period *= random.randint(75, 90) / 100.0
          else:
              xmit_period *= random.randint(75, 100) / 100.0
  
          self._xmit_period = xmit_period / 1000000.0
          LOG.info("[BFD][%s][XMIT] Transmission period changed to %f",
                   hex(self._local_discr), self._xmit_period)
docs: Update transmission period of the BFD session.