def test_default_func_empty(self):
        """
        dumps() default function no explicit return
        """
        ref = Custom()

        def default(obj):
            if isinstance(obj, set):
                return list(obj)

        assert orjson.dumps(ref, default=default) == b"null"
        assert orjson.dumps({ref}, default=default) == b"[null]"

        dumps() default function no explicit return
        
test/test_default.py