def driver(self):
        """
        Return the driver of this agent related to. None if the driver is not ready to bind.

        Returns:
            :py:class:`inherit from Poco <poco.pocofw.Poco>`: the driver of this agent related to.
        """

        if not self._driver:
            raise AttributeError("`driver` is not bound on this agent implementation({}). "
                                 "Do you forget to call `super().on_bind_driver` when you override the method "
                                 "`on_bind_driver` in your sub class?"
                                 .format(repr(self)))
        return self._driver