使用Singleton的Ruby C扩展

void Init_mousetest() {
    VALUE mouseclass = rb_define_class("MyMouse",rb_cObject);
    rb_require("singleton");
    VALUE singletonmodule = rb_const_get(rb_cObject,rb_intern("Singleton"));
    rb_include_module(mouseclass,singletonmodule);

    rb_funcall(singletonmodule,rb_intern("included"),1,mouseclass);
### ^ Why do I need this line here?

    rb_define_method(mouseclass,"run",method_run,0);
    rb_define_method(mouseclass,"spawn",method_spawn,0);
    rb_define_method(mouseclass,"stop",method_stop,0);
}

Singleton.included(MyMouse) 但如果我试着调用它

irb(main):006:0> Singleton.included(MyMouse)
NoMethodError: private method `included' called for Singleton:Module
        from (irb):6
        from C:/Ruby19/bin/irb:12:in `<main>'

为什么会这样 rb_include_module

而且,我似乎可以保持我的扩展尽可能简单,只是黑客某种接口以后,以确保我只允许一个实例。或者把鼠标相关的方法放到一个模块里。。。这些有道理吗?