GraphQL\Language\Lexer::assertValidStringCharacterCode PHP Method

    private function assertValidStringCharacterCode($code, $position)
    {
        // SourceCharacter
        if ($code < 0x20 && $code !== 0x9) {
            throw new SyntaxError($this->source, $position, 'Invalid character within String: ' . Utils::printCharCode($code));
        }
    }