Error with variable

Running WordPress 6.3.1

Getting error:

Only variables should be assigned by reference in <b>/home/…../public_html/……./wordpress/wp-content/plugins/exclude-pages/exclude_pages.php</b> on line <b>92</b>

Function in exclude_pages.php is:

function ep_ancestor_excluded( $page, $excluded_ids, $pages ) {
$parent = & ep_get_page( $page->post_parent, $pages );
// Is there a parent?
if ( ! $parent )
return false;
// Is it excluded?
if ( in_array( $parent->ID, $excluded_ids ) )
return (int) $parent->ID;
// Is it the homepage?
if ( $parent->ID == 0 )
return false;
// Otherwise we have another ancestor to check
return ep_ancestor_excluded( $parent, $excluded_ids, $pages );
}

where line 92 is

$parent = & ep_get_page( $page->post_parent, $pages );

I don’t know what this error means.