UPC.

        :return:
            UPC (string)

def upc(self):
        """UPC.

        :return:
            UPC (string)
        """
        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