code: func Sample(population []interface{}, k int) (res []interface{}, err error) {
  	n := len(population)
  	idxs, err := SampleInts(n, k)
  	if err != nil {
  		return
  	}
  
  	res = []interface{}{}
  	for _, idx := range idxs {
  		res = append(res, population[idx])
  	}
  
  	return
  }
docs: // Samples 'k' elements from the given slice