code: func (ung UniformGenerator) Shuffle(arr []interface{}) {
  	N := len(arr)
  	for i := range arr {
  		r := int32(i) + ung.Int32n(int32(N-i))
  		arr[i], arr[r] = arr[r], arr[i]
  	}
  }
docs: // Shuffle rearrange the elements of an array in random order