How to Hide the "Warp iMagick" Admin Menu

function plt_hide_warp_imagick_menus() {
	//Hide the "Media → Warp iMagick" menu.
	remove_submenu_page('upload.php', 'warp-imagick');
}

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

Where do I put this code?