Perform POST /rooms/$room_id/unban

        Args:
            room_id (str): The room ID
            user_id (str): The user ID of the banee(sic)

def unban_user(self, room_id, user_id):
        """Perform POST /rooms/$room_id/unban

        Args:
            room_id (str): The room ID
            user_id (str): The user ID of the banee(sic)
        """
        body = {
            "user_id": user_id
        }
        return self._send("POST", "/rooms/" + room_id + "/unban", body)