Child page codes are making my pages disappear

I have this code right above my h2 in page.php

<?php

$args = array(
‘child_of’ => get_top_ancestor_id(),
‘title_li’ => ”
);
?>

<?php wp_list_pages($args); ?>

and this code in functions.php

function get_top_ancestor_id() {

global $post;

if($post->post_parent) {
$ancestors = array_reverse(get_post_ancestors(post->ID));
return $ancestors[0];
}

return $post->ID;
}

Can someone please tell me if there’s anything wrong with the code? I can’t find anything.