public MethodBuilder onthrow(Object onthrow) {
        this.onthrow = onthrow;
        return getThis();
    }
@Test
    void onthrow() {
        MethodBuilder builder = MethodBuilder.newBuilder();
        builder.onthrow("on-throw-object");
        Assertions.assertEquals("on-throw-object", builder.build().getOnthrow());
    }