# File lib/kwala/lib/cycle_detector.rb, line 405
    def make_clusters(keys)
      groups = Hash.new { |h,k| h[k] = Array.new }

      keys.sort.each do |k|
        if k.include?("/")
          spname = k.split("/")
          gname = spname[0..-2].join("/")
        else
          gname = DEFAULTCLUSTER
        end
        groups[gname] << k
      end

      sub_group_clusters(groups)
    end