code: def upc(self):
          
          upc = self._safe_get_element_text('ItemAttributes.UPC')
          if upc is None:
              upc_list = self._safe_get_element_text('ItemAttributes.UPCList')
              if upc_list:
                  upc = self._safe_get_element_text(
                      'UPCListElement', root=upc_list[0])
          return upc
docs: UPC.
  
          :return:
              UPC (string)