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