code: func Bounds(xs []float64) (min float64, max float64) {
  	if len(xs) == 0 {
  		return math.NaN(), math.NaN()
  	}
  	min, max = xs[0], xs[0]
  	for _, x := range xs {
  		if x < min {
  			min = x
  		}
  		if x > max {
  			max = x
  		}
  	}
  	return
  }
docs: // Bounds returns the minimum and maximum values of xs.