jstraitlets.py 文件源码

def visit_Union(self, trait, dct, *args, **kwargs):
        try:
            return self.generic_visit(trait, dct)
        except T.TraitError:
            for subtrait in trait.trait_types:
                try:
                    return self.visit(subtrait, dct)
                except T.TraitError:
                    pass
            raise  # no valid trait found