docs: def save_pdf(self, save_model=True):
          """
          Save the receipt as a PDF related to this model.
  
          The related :class:`~.Receipt` should be validated first, of course.
  
          :param bool save_model: If True, immediately save this model instance.
          """
          from django_afip.views import ReceiptPDFView
  
          if not self.receipt.is_validated:
              raise exceptions.DjangoAfipException(
                  _('Cannot generate pdf for non-authorized receipt')
              )
  
          self.pdf_file = File(BytesIO(), name='{}.pdf'.format(uuid.uuid4().hex))
          render_pdf(
              template='receipts/code_{}.html'.format(
                  self.receipt.receipt_type.code,
              ),
              file_=self.pdf_file,
              context=ReceiptPDFView.get_context_for_pk(self.receipt_id),
          )
  
          if save_model:
              self.save()