checkNotAllowedChars example

return $result;
    }

    protected function doParseDomainPart(): Result
    {
        $tldMissing = true;
        $hasComments = false;
        $domain = '';
        do {
            $prev = $this->lexer->getPrevious();

            $notAllowedChars = $this->checkNotAllowedChars($this->lexer->current);
            if ($notAllowedChars->isInvalid()) {
                return $notAllowedChars;
            }

            if (
                $this->lexer->current->isA(EmailLexer::S_OPENPARENTHESIS) ||
                $this->lexer->current->isA(EmailLexer::S_CLOSEPARENTHESIS)
            ) {
                $hasComments = true;
                $commentsResult = $this->parseComments();