    # File lib/facets/core/module/attr_query.rb, line 26
      def attr_tester(*args)
        make = {}
        args.each { |a|
          make["#{a}?".to_sym] = %{ def #{a}?; @#{a} ? true : @#{a}; end }
          make["#{a}!".to_sym] = %{
            def #{a}!(switch=nack)
              if switch==nack
                @#{a} = !@#{a}
              else
                @#{a} = @#{a} ? switch : @#{a}
                self
              end
            end
          }
        }
        module_eval make.values.join("\n")

        return make.keys
      end