# File lib/ai4r/classifiers/hyperpipes.rb, line 95
      def build_pipe(data_set)
        data_set.data_items.first[0...-1].collect do |att|
          if att.is_a? Numeric
            {:min=>1.0/0, :max=>-1.0/0}
          else
            Hash.new(false)
          end
        end
      end