Dynamically creating enum attributes

I can't manage to dynamically create a DevEnum attribute in pytango 9. Statically defined enum attributes appear to work, but as far as I've been able to figure out, I should be able to do something like:

attr = tango.AttrData(
                "MyNiceEnum", None,
                attr_info=[
                    (
                        tango.DevEnum,
                        tango.SCALAR,
                        tango.READ
                    ), {
                        "enum_labels": ["A", "B", "C"]  # no workee!
                    }
                ])
self.add_attribute(attr, r_meth=self.read_MyNiceEnum)

The attribute gets added, but it does not have any labels configured.