custom3 - function child or no child pages

 //attempt creating a test child page function
<?php function testchildren () {
    $children = get_pages('child_of='.$post->ID);
    if( count( $children ) != 0 )  {
        echo 'has NO children';
        return $nochildren;
        }
    else
        {
        echo 'has children';
        return $haschildren;
        }
}
?>


<!-- basic loop -->
<?php if (have_posts()) : while (have_posts()) : the_post() ; ?>
<h2>
    <?php $parent_title = get_the_title($post->post_parent); echo $parent_title; ?>
</h2>

<?php testchildren (); ?>

     <h1 style="margin-bottom:12px"><?php the_title(); ?></h1>


    <?php the_content(); ?>
<?php endwhile; endif; ?>