Wordpress: get hierarchical post ancestor

functions.php

/**
 * get hierarchical post ancestor (level 0)
 *
 * @param int|object $post
 * @return object post ancestor
 *
 * @usage get_post_ancestor(131) | get_post_ancestor($post)
 *
**/
function get_post_ancestor( $post = false ) {
	if ( !is_object($post) ) {
		$post = get_post($post);
	}

	if ( !$post || empty($post->ancestors) ) {
		return;
	}
	
	return get_post( end( $post->ancestors ) );
}