code: func (c *Corpus) Word(id int) (string, bool) {
  	size := atomic.LoadInt64(&c.maxid)
  	maxid := int(size)
  
  	if id >= maxid {
  		return "", false
  	}
  	return c.words[id], true
  }
docs: // Word returns the word given the ID, and whether or not it was found in the corpus