code: func (c *Class) DefineClassMethod(name string, cb Func, as ArgSpec) {
  	insertMethod(c.mrb.state, c.class.c, name, cb)
  
  	cs := C.CString(name)
  	defer C.free(unsafe.Pointer(cs))
  
  	C.mrb_define_class_method(
  		c.mrb.state,
  		c.class,
  		cs,
  		C._go_mrb_func_t(),
  		C.mrb_aspec(as))
  }
docs: // DefineClassMethod defines a class-level method on the given class.