* @return LLMS_REST_API_Key|WP_Error
	 */
	protected static function save_update( $key_id ) {

		$key = LLMS_REST_API()->keys()->get( $key_id );
		if ( ! $key ) {
			// Translators: %s = Invalid API Key ID.
			return new WP_Error( 'llms_rest_api_key_not_found', sprintf( __( '"%s" is not a valid API Key.', 'lifterlms' ), $key_id ) );
		}

		$update = LLMS_REST_API()->keys()->update(
			array(
				'id'          => $key_id,
				'description' => llms_filter_input_sanitize_string( INPUT_POST, 'llms_rest_key_description' ),
				'user_id'     => llms_filter_input( INPUT_POST, 'llms_rest_key_user_id', FILTER_SANITIZE_NUMBER_INT ),
				'permissions' => llms_filter_input_sanitize_string( INPUT_POST, 'llms_rest_key_permissions' ),
			)
		);

		return $update;