How to Hide Stylish Price List Admin Menus

function plt_hide_stylish_price_list_menus() {
	//Hide "Stylish Price List".
	remove_menu_page('spl-tabs');
	//Hide "Stylish Price List → All Lists".
	remove_submenu_page('spl-tabs', 'spl-tabs');
	//Hide "Stylish Price List → Add New List".
	remove_submenu_page('spl-tabs', 'spl-tabs-new');
	//Hide "Stylish Price List → SPL Diagnostic".
	remove_submenu_page('spl-tabs', 'spl-tabs-diagnostic');
	//Hide "Stylish Price List → Help".
	remove_submenu_page('spl-tabs', 'stylish_price_list_help');
	//Hide "Stylish Price List → Video Tutorials".
	remove_submenu_page('spl-tabs', 'stylish_price_list_video');
	//Hide "Stylish Price List → Settings".
	remove_submenu_page('spl-tabs', 'stylish_price_list_settings');
	//Hide "Stylish Price List → License".
	remove_submenu_page('spl-tabs', 'stylish_price_list_license');
}

add_action('admin_menu', 'plt_hide_stylish_price_list_menus', 91);

Where do I put this code?