code: def send(self, msg):
          
          assert isinstance(msg, str), "String is required"
  
          if self._debug:
              log.info("outgoing message: %s, %s", self.id, str(msg)[:200])
  
          if self.state != STATE_OPEN:
              return
  
          self._feed(FRAME_MESSAGE, msg)
docs: send message to client.