code: func (m *Mrb) DefineClass(name string, super *Class) *Class {
  	if super == nil {
  		super = m.ObjectClass()
  	}
  
  	cs := C.CString(name)
  	defer C.free(unsafe.Pointer(cs))
  
  	return newClass(
  		m, C.mrb_define_class(m.state, cs, super.class))
  }
docs: //-------------------------------------------------------------------
  // Functions handling defining new classes/modules in the VM
  //-------------------------------------------------------------------
  // DefineClass defines a new top-level class.
  //
  // If super is nil, the class will be defined under Object.