Backend\Modules\Extensions\Engine\Model::existsTemplate PHP Method

    public static function existsTemplate($id)
    {
        return (bool) BackendModel::getContainer()->get('database')->getVar('SELECT i.id FROM themes_templates AS i WHERE i.id = ?', array((int) $id));
    }

 /**
  * Execute the action
  */
 public function execute()
 {
     // get parameters
     $this->id = $this->getParameter('id', 'int');
     // does the item exist
     if ($this->id !== null && BackendExtensionsModel::existsTemplate($this->id)) {
         // call parent, this will probably add some general CSS/JS or other required files
         parent::execute();
         // init var
         $success = false;
         // get template (we need the title)
         $item = BackendExtensionsModel::getTemplate($this->id);
         // valid template?
         if (!empty($item)) {
             // delete the page
             $success = BackendExtensionsModel::deleteTemplate($this->id);
             // trigger event
             BackendModel::triggerEvent($this->getModule(), 'after_delete_template', array('id' => $this->id));
         }
         // page is deleted, so redirect to the overview
         if ($success) {
             $this->redirect(BackendModel::createURLForAction('ThemeTemplates') . '&theme=' . $item['theme'] . '&report=deleted-template&var=' . urlencode($item['label']));
         } else {
             $this->redirect(BackendModel::createURLForAction('ThemeTemplates') . '&error=non-existing');
         }
     } else {
         // something went wrong
         $this->redirect(BackendModel::createURLForAction('ThemeTemplates') . '&error=non-existing');
     }
 }