public function addFile($file, $name = 'attachment', $mime = Mime::TXT) {
        $this->_fileTransfert = 'multipart/mixed';
        $this->_hasAttachment = true;

        if (file_exists($file)) {
            $data = file_get_contents($file);

            if ($name == self::ATTACHMENT) {
                $name = $name . uniqid();
            }

            if (isset($this->_attachments[$name])) {
                $name = $name . uniqid();
            }

            $this->_attachments[$name] = [chunk_split(base64_encode($data), $mime)];
        }
    }