parent_menu_slug = $parent_menu_slug; $this->menu_slug = 'amp-analytics-options'; $this->menu_page = new AMP_Analytics_Options_Submenu_Page(); } public function init() { $this->add_submenu(); add_action( 'admin_print_styles-amp_page_' . $this->menu_slug, array( $this, 'amp_options_styles' ) ); } private function add_submenu() { add_submenu_page( $this->parent_menu_slug, __( 'AMP Analytics Options', 'amp' ), __( 'Analytics', 'amp' ), 'manage_options', $this->menu_slug, array( $this->menu_page, 'render' ) ); } public function amp_options_styles() { ?> ;