true, 'single' => true, 'type' => 'string', 'default' => self::get_default_value(), 'auth_callback' => '__return_true', ); foreach ( array( 'post', 'page' ) as $post_type ) { register_post_meta( $post_type, self::META_NAME, $args ); } } public static function is_valid_meta_value( $meta_value ) { return in_array( $meta_value, array( 'inherit', 'enable', 'disable' ), true ); } }