Contao\Email::compileRecipients PHP Method

    protected function compileRecipients($arrRecipients)
    {
        $arrReturn = array();
        foreach ($arrRecipients as $varRecipients) {
            if (!is_array($varRecipients)) {
                $varRecipients = \StringUtil::splitCsv($varRecipients);
            }
            // Support friendly name addresses and internationalized domain names
            foreach ($varRecipients as $v) {
                list($strName, $strEmail) = \StringUtil::splitFriendlyEmail($v);
                $strName = trim($strName, ' "');
                $strEmail = \Idna::encodeEmail($strEmail);
                if ($strName != '') {
                    $arrReturn[$strEmail] = $strName;
                } else {
                    $arrReturn[] = $strEmail;
                }
            }
        }
        return $arrReturn;
    }