code: def start(self):
          
  
          self.receiver = self.Receiver(
              self.read,
              self.write,
              self.send_lock,
              self.senders,
              self.frames_received,
              callback=self.receive_callback,
              fcs_nack=self.fcs_nack,
          )
  
          self.receiver.start()
docs: Starts HDLC controller's threads.