Core/Mailer/AbstractMail.php
public function addReplytos(array $reply_tos)
    {
        foreach ($reply_tos as $key => $val) {
            if (is_numeric($key)) {
                $this->addReplyto($val);
            } else {
                $this->addReplyto($key, $val);
            }
        }
    }
public function addReplytos(array $reply_tos)
    {
        foreach ($reply_tos as $key => $val) {
            if (is_numeric($key)) {
                $this->addReplyto($val);
            } else {
                $this->addReplyto($key, $val);
            }
        }
    }
Adds a list of contacts to the replytolist

@param array $reply_tos
List of contacts to add. This array can be an indexed array with only
the contacts mailaddress or an assoc array with mailaddress as key and
the contacts name as value.