code: def update_invoice_item(self, invoice_item_id, invoice_item_dict):
          
          return self._create_put_request(
              resource=INVOICE_ITEMS,
              billomat_id=invoice_item_id,
              send_data=invoice_item_dict
          )
docs: Updates an invoice item
  
          :param invoice_item_id: the invoice item id
          :param invoice_item_dict: dict
          :return: dict