object.c:707
static VALUE
rb_class_initialize(argc, argv, klass)
    int argc;
    VALUE *argv;
    VALUE klass;
{
    VALUE super;

    if (RCLASS(klass)->super != 0) {
	rb_raise(rb_eTypeError, "already initialized class");
    }
    if (rb_scan_args(argc, argv, "01", &super) == 0) {
	super = rb_cObject;
    }
    RCLASS(klass)->super = super;
    rb_make_metaclass(klass, RBASIC(super)->klass);
    rb_mod_initialize(klass);
    rb_class_inherited(super, klass);

    return klass;
}
