def METHOD_NAME(self, user, key):
    username = user.username
    existing_user_config = self.db_userconfig.query(UserConfig) \
        .filter(UserConfig.user_login == username).all()
    if len(existing_user_config) > 0:
        for config in existing_user_config:
            self.db_userconfig.query(UserConfig).filter(
                UserConfig.id == config.id,
                UserConfig.key == key
            ).delete()