GraphQL\Validator\Rules\KnownTypeNames::unknownTypeMessage PHP Method

    static function unknownTypeMessage($type)
    {
        return "Unknown type \"{$type}\".";
    }

 private function unknownType($typeName, $line, $column)
 {
     return FormattedError::create(KnownTypeNames::unknownTypeMessage($typeName), [new SourceLocation($line, $column)]);
 }