protected function clientExists(&$text, $fieldName)
 {
     $clientModel = new Admin_Model_Client();
     $result = $clientModel->fetchRow(K_Db_Select::create()->where(array('client_id' => $text)));
     if (count($result)) {
         return true;
     }
     $this->errors[$fieldName] = 'Такого клиента не существует';
     return false;
 }