/**
  * @param InvoiceInterface $invoice
  *
  * @return $this
  */
 private function checkInvoice(InvoiceInterface $invoice)
 {
     if ($invoice->isFilled()) {
         $this->groups[] = self::INVOICE_GROUP;
     }
     return $this;
 }
 /**
  * @param  InvoiceInterface   $invoice
  * @param  string             $propertyName
  * @param  string             $value
  * @return InvoiceTransformer
  */
 private function copyRecipientValue(InvoiceInterface $invoice, $propertyName, $value)
 {
     switch ($propertyName) {
         case TransformerProperties::INVOICE_RECIPIENT_EMAIL:
             $invoice->setRecipientEmail($value);
             break;
         case TransformerProperties::INVOICE_RECIPIENT_NAME:
             $invoice->setRecipientName($value);
             break;
         case TransformerProperties::INVOICE_RECIPIENT_PHONE:
             $invoice->setRecipientPhone($value);
             break;
         case TransformerProperties::INVOICE_RECIPIENT_TIN:
             $invoice->setRecipientTin($value);
             break;
     }
     return $this;
 }