def getCounts
      result = {}
      @classes.each do |c|
        count = 0
        ObjectSpace.each_object(c){ count += 1 }
        result[c] = count
      end
      result
    end
def getCounts
      result = {}
      @classes.each do |c|
        count = 0
        ObjectSpace.each_object(c){ count += 1 }
        result[c] = count
      end
      result
    end
Return a hashtable keyed by class where the value is the number of that class of object still reachable.