def add(self, handler, priority=10):
        """
        Add handler.

        :param callable handler: callable handler
        :return callable: The handler you added is given back so this can be used as a decorator.
        """
        self.container.add_handler(handler, priority=priority)
        return handler
Add handler.

        :param callable handler: callable handler
        :return callable: The handler you added is given back so this can be used as a decorator.