public function getSender()
    {
        if (!empty($this->sender)) {
            $sender = '';
            if (!empty($this->sender[1])) {
                $sender .= $this->addEncodeTag('"' . $this->sender[1] . '"') . ' ';
            }
            $sender .= '<' . $this->sender[0] . '>';
            return $sender;
        } else {
            return false;
        }
    }