protected function error($message = '', $group = 'Other', array $caller = NULL)
 {
     if ($message == 'Undefined variable: location') {
         // change error (Notice) to debug message
         return $this->assert('debug', $message, 'Debug', $caller);
     }
     if ($message == 'Undefined property: stdClass::$locations') {
         // change error (Notice) to debug message
         return $this->assert('debug', $message, 'Debug', $caller);
     }
     return parent::error($message, $group, $caller);
 }