code: func (h *NumericHistogram) String() (str string) {
  	str += fmt.Sprintln("Total:", h.total)
  
  	for i := range h.bins {
  		var bar string
  		for j := 0; j < int(float64(h.bins[i].count)/float64(h.total)*200); j++ {
  			bar += "."
  		}
  		str += fmt.Sprintln(h.bins[i].value, "\t", bar)
  	}
  
  	return
  }
docs: // String returns a string reprentation of the histogram,
  // which is useful for printing to a terminal.