a::missing PHP Method

    static function missing($array, $required = array())
    {
        $missing = array();
        foreach ($required as $r) {
            if (empty($array[$r])) {
                $missing[] = $r;
            }
        }
        return $missing;
    }

 public function create($uid, $template, $content = array())
 {
     if (empty($template)) {
         throw new Exception(l('pages.add.error.template'));
     }
     $uid = empty($uid) ? str::random(32) : $uid;
     $blueprint = new Blueprint($template);
     $data = array();
     foreach ($blueprint->fields(null) as $key => $field) {
         $data[$key] = $field->default();
     }
     $data = array_merge($data, $content);
     // create the new page and convert it to a page model
     $page = new Page($this->page, parent::create($uid, $template, $data)->dirname());
     if (!$page) {
         throw new Exception(l('pages.add.error.create'));
     }
     kirby()->trigger('panel.page.create', $page);
     // subpage builder
     foreach ((array) $page->blueprint()->pages()->build() as $build) {
         $missing = a::missing($build, array('title', 'template', 'uid'));
         if (!empty($missing)) {
             continue;
         }
         $subpage = $page->children()->create($build['uid'], $build['template'], array('title' => $build['title']));
         if (isset($build['num'])) {
             $subpage->sort($build['num']);
         }
     }
     return $page;
 }