gtm4wp in Oxygen

<?php

add_action( 'ct_before_builder', 'gtm4wp_for_oxygen' );
/**
 * Adds gtm4wp tag code immediately after the opening <body> tag in Oxygen.
 */
function gtm4wp_for_oxygen() {

    if ( function_exists( 'gtm4wp_the_gtm_tag' ) ) {
        gtm4wp_the_gtm_tag();
    }
}