Ruby模块中的私有类(非类方法)?

I'm new to Ruby (experienced with Python, C++ and C). I need to create a class that is only to be used by other classes and methods in a module. In Python, I'd just call it __classname. I'd use an empty typedef in C++. How do I do this in Ruby (or am I barking up the wrong tree and not doing this the "Ruby way"?)I'm new to Ruby (experienced with Python, C++ a