您好，我的自定义插件有问题：/

警告：call\\u user\\u func\\u array（）要求参数1为有效回调，在C:\\xampp\\htdocs\\wordpress\\wp includes\\plugin中找不到函数“wp\\u slider\\u info\\u page”，或函数名无效。php在线496

我找到了很多关于这个警告的话题，但我仍然不知道是什么错了/

if ( !class_exists( \'wp_slider\' ) ) {

    class wp_slider{

        function __construct() {

            add_action( \'admin_menu\', array( $this, \'wp_slider_info\' ) );
            add_action( \'slider-style\', array( $this, \'slider_styles\') );
            add_action( \'slider-script\', array( $this, \'slider_scripts\') );

            add_filter( \'the_content\', array( $this, \'wp_slider_info_page\') );

            register_activation_hook( __FILE__, array( $this, \'wp_install\' ) );
            register_deactivation_hook(__FILE__, array( $this, \'wp_uninstall\' ) );
        }

        function wp_slider_info(){

            add_menu_page(\'wp Slider\', \'wp Slider\', \'administrator\', \'slider-info\', \'wp_slider_info_page\', \'dashicons-format-video\');
        }

        function wp_install(){
            global $wpdb;
            $table_name=$wpdb->prefix.\'wp_slider\';
            $sql="CREATE TABLE $table_name (
            id int(11) NOT NULL AUTO_INCREMENT,
            image varchar(255) NOT NULL,
            link varchar(255) NOT NULL,
            title varchar(255) NOT NULL,
            content text NULL,
            UNIQUE KEY id (id)
            );";

            require_once( ABSPATH . \'wp-admin/includes/upgrade.php\' );
            dbDelta( $sql );
        }

        function wp_uninstall(){
            global $wpdb;
            $table_name=$wpdb->prefix.\'wp_slider\';
            $sql=\'DROP TABLE \'.$table_name;
                $wpdb->query($sql);
        }

        public function slider_scripts() {

            if (!is_admin()) {
                wp_register_style(\'slider-script\', plugins_url(\'slider-script.js\', __FILE__), array( \'jquery\' ));
                wp_enqueue_style(\'slider-script\');
            }
        }

        public function slider_styles( $page ) {

            wp_register_style(\'slider-style\', plugins_url(\'slider-style.css\', __FILE__));
            wp_enqueue_style(\'slider-style\');
        }

        function wp_slider_info_page( $content ){

            return $content . \'<p>Test</p>\';
        }

    }

    new wp_slider();

}