class MyException1(msg: Str): Exception(msg)
class MyException2(msg: Str): Exception(msg)
def f(x: Int) -> Int raise [MyException1, MyException2] =>
match x
0 => 20
1 => raise MyException1()
2 => raise MyException2()
def g() -> Int raise [MyException2] =>
f(2) handle
err: MyException1 => 10
g()