public function display_error()
{
if (!is_a($this->error, 'WP_Error')) {
return;
}
$message = self::$instance->error->get_error_messages();
?>
<div class="error">
<p>
<?php
if (count($message) > 1) {
echo '<ul>';
foreach ($message as $msg) {
echo "<li>{$msg}</li>";
}
echo '</li>';
} else {
echo $message[0];
}
?>
</p>
</div>
<?php
}