<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def request(self, msgtype, msgid, method, params=[]):
 """Handle an incoming call request."""

        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)