How to Hide Insert PHP Code Snippet Admin Menus

function plt_hide_insert_php_code_snippet_menus() {
	//Hide "Insert PHP Code Snippet".
	remove_menu_page('insert-php-code-snippet-manage');
	//Hide "Insert PHP Code Snippet → PHPCode Snippets".
	remove_submenu_page('insert-php-code-snippet-manage', 'insert-php-code-snippet-manage');
	//Hide "Insert PHP Code Snippet → Settings".
	remove_submenu_page('insert-php-code-snippet-manage', 'insert-php-code-snippet-settings');
	//Hide "Insert PHP Code Snippet → About".
	remove_submenu_page('insert-php-code-snippet-manage', 'insert-php-code-snippet-about');
	//Hide "Insert PHP Code Snippet → Suggest a Feature".
	remove_submenu_page('insert-php-code-snippet-manage', 'insert-php-code-snippet-suggest-features');
}

add_action('admin_menu', 'plt_hide_insert_php_code_snippet_menus', 11);

Where do I put this code?