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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def link_rich_menu_to_user(self, user_id, rich_menu_id, timeout=None):
 """Call link rich menu to user API. https://developers.line.me/en/docs/messaging-api/reference/#link-rich-menu-to-user :param str user_id: ID of an uploaded rich menu :param str rich_menu_id: ID of the user :type timeout: float | tuple(float, float) """

        self._post(
            '/v2/bot/user/{user_id}/richmenu/{rich_menu_id}'.format(
                user_id=user_id,
                rich_menu_id=rich_menu_id
            ),
            timeout=timeout
        )