def METHOD_NAME(self) -> None:
    fx = self.fx
    assert infer_constraints(
        Instance(fx.gvi, [UnpackType(fx.ts)]), Instance(fx.gvi, [fx.a, fx.b]), SUBTYPE_OF
    ) == [
        Constraint(type_var=fx.ts, op=SUBTYPE_OF, target=TupleType([fx.a, fx.b], fx.std_tuple))
    ]