code: def request(self, msgtype, msgid, method, params=[]):
          
          result = None
          error = None
          exception = None
  
          try:
              result = self.dispatch.call(method, params)
          except Exception as e:
              error = (e.__class__.__name__, str(e))
              exception = e
  
          if isinstance(result, Deferred):
              result.add_callback(self._result, msgid)
              result.add_errback(self._error, msgid)
          else:
              self.send_response(msgid, error, result)
docs: Handle an incoming call request.