isMultiPart example

    public function generateMessage($EOL = Zend_Mime::LINEEND)
    {
        if (! $this->isMultiPart()) {
            $body = array_shift($this->_parts);
            $body = $body->getContent($EOL);
        } else {
            $mime = $this->getMime();

            $boundaryLine = $mime->boundaryLine($EOL);
            $body = 'This is a message in Mime Format. If you see this, '
                  . "your mail reader does not support this format." . $EOL;

            foreach (array_keys($this->_parts) as $p) {
                $body .= $boundaryLine
                       .