code: def find_connection(self):
          '''find an antenna tracker connection if possible'''
          if self.connection is not None:
              return self.connection
          for m in self.mpstate.mav_master:
              if 'HEARTBEAT' in m.messages:
                  if m.messages['HEARTBEAT'].type == mavutil.mavlink.MAV_TYPE_ANTENNA_TRACKER:
                      return m
          return Nonf find_connection(self):
          '''find an antenna tracker connection if possible'''
          if self.connection is not None:
              return self.connection
          for m in self.mpstate.mav_master:
              if 'HEARTBEAT' in m.messages:
                  if m.messages['HEARTBEAT'].type == mavutil.mavlink.MAV_TYPE_ANTENNA_TRACKER:
                      return m
          return None
docs: find an antenna tracker connection if possible