<?php
$node = menu_get_object();
if ( !empty($node)  && $node->type == 'class' ) {
  if ( !empty($node->field_class_date) && !empty($node->field_class_date['und']) && !empty($node->field_class_date['und'][0]) ) {
     $parts = explode('T', $node->field_class_date['und'][0]['value']);
     $date_parts =  explode('-', $parts[0]);
     $class_date = $date_parts[1] . '/' . $date_parts[2] . '/' . $date_parts[0] . ' ' .  $parts[1];
     $on = strtotime($class_date);
     $now = time();
     if ( $on >= $now ) {
        return TRUE;
     }
  }
}
return FALSE;
?>

<?php
    $match = FALSE;
    $types = array('date' => 1);
    if (arg(0) == 'node' && is_numeric(arg(1) )) {
    $nid = arg(1);
    $node = node_load(array('nid' => $nid));
    $type = $node->type;
    if (isset($types[$type])) {
    $match = TRUE;
    }
   }
    return $match;
   ?>