GraphQL\Validator\Rules\KnownFragmentNames::unknownFragmentMessage PHP Метод

    static function unknownFragmentMessage($fragName)
    {
        return "Unknown fragment \"{$fragName}\".";
    }

 private function undefFrag($fragName, $line, $column)
 {
     return FormattedError::create(KnownFragmentNames::unknownFragmentMessage($fragName), [new SourceLocation($line, $column)]);
 }