The _get_unece_code method does not work in case where a specific uom has multiple xml_ids. Change it to handle such case and try to match every xml ids with a unece code if possible. closes odoo/odoo#91076 X-original-commit: d488b3cde3701b5eb69ac36cb6bbcc913956a0d4 Signed-off-by: Florian Gilbert <flg@odoo.com>