Pimcore\Mail::setDocument PHP Method

    public function setDocument($document)
    {
        if ($document instanceof Model\Document) {
            //document passed
            $this->document = $document;
            $this->setDocumentSettings();
        } elseif ((int) $document > 0) {
            //id of document passed
            $this->setDocument(Model\Document::getById($document));
        } elseif (is_string($document) && $document != "") {
            //path of document passed
            $this->setDocument(Model\Document::getByPath($document));
        } else {
            throw new \Exception("{$document} is not an instance of \\Document\\Email or at least \\Document");
        }
        return $this;
    }

 /**
  * Process OrderState for Order
  *
  * @param CoreShopOrder $order
  * @param null $locale
  * @return bool
  * @throws \Exception
  */
 public function processStep(CoreShopOrder $order, $locale = null)
 {
     $emailDocument = $this->getEmailDocument($locale);
     $emailParameters = array("order" => $order, "newOrderStatus" => $this, "user" => $order->getCustomer());
     if ($this->getAccepted()) {
     }
     if ($this->getShipped()) {
     }
     if ($this->getPaid()) {
         Plugin::actionHook("paymentConfirmation", array("order" => $order));
     }
     Plugin::actionHook("orderStatusUpdate", array("newOrderStatus" => $this, "order" => $order));
     if ($this->getEmail() && $emailDocument instanceof Document\Email) {
         $mail = new Mail();
         $mail->setDocument($emailDocument);
         $mail->setParams($emailParameters);
         $mail->addTo($order->getCustomer()->getEmail(), $order->getCustomer()->getFirstname() . " " . $order->getCustomer()->getLastname());
         Tool::addAdminToMail($mail);
         $mail->send();
     }
     $order->setOrderState($this);
     $order->save();
     return true;
     //TODO: Stock Management
 }