<card xmlns=“www.example.com”
xmlns:a="http://www.example.com/a" a:foo="works" xmlns:b="http://www.example.com" b:foo="fails"> This should fail
</card>
<card xmlns=“www.example.com”
xmlns:a="http://www.example.com/a" a:foo="works" xmlns:b="http://www.example.com" b:foo="fails"> This should fail
</card>