protected function getErrorString($code, $value, $default = null)
    {
        if (array_key_exists($code, $this->translatable_errors)) {
            $resolver = $this->translatable_errors[$code];
            if ($resolver instanceof Closure) {
                return $resolver($this, $code, $value);
            } else {
                return $resolver;
            }
        }

        return $default;
    }