code: public static void mixin(MetaClass self, List<Class> categoryClasses) {
          MixinInMetaClass.mixinClassesToMetaClass(self, categoryClasses);
      }
docs: Extend object with category methods.
  All methods for given class and all super classes will be added to the object.
  
  @param self          any Class
  @param categoryClasses a category classes to use
  @since 1.6.0