我目前在父页ID 43下有两个子页。客户证明。。无论如何我在查询$args中有随机顺序，但顺序从未改变。我会错过什么？

wp_reset_query();
$args=array(
  \'post_parent\' => 43,
  \'post_type\' => \'page\',
  \'post_status\' => \'publish\',
  \'posts_per_page\' => 2, 
  \'orderby\'=>\'rand\'
);
$my_query = new WP_Query($args);
if( $my_query->have_posts() ) {
    while ($my_query->have_posts()) : $my_query->the_post();
    ?>
    <h4><? echo get_post_meta($post->ID,\'subtitle\', true);?></h4>
    <p><? echo get_the_excerpt(); ?></p>
    <?
    endwhile;
}
wp_reset_query();  // Restore global post data stomped by the_post().