def included_constants
      instance_mixins.inject([]) do |list, mixin|
        if mixin.respond_to? :constants
          list += mixin.constants.reject do |o|
            child(:name => o.name) || list.find {|o2| o2.name == o.name }
          end
        else
          list
        end
      end
    end
def included_constants
      instance_mixins.inject([]) do |list, mixin|
        if mixin.respond_to? :constants
          list += mixin.constants.reject do |o|
            child(:name => o.name) || list.find {|o2| o2.name == o.name }
          end
        else
          list
        end
      end
    end
Returns constants included from any mixins
 @return [Array<ConstantObject>] a list of constant objects