code: func (as AnnotatedSentence) LoweredStringSlice() []string {
  	retVal := make([]string, len(as), len(as))
  	for i, a := range as {
  		retVal[i] = a.Lowered
  	}
  	return retVal
  }
docs: // LoweredStringSlice returns the lowercased version of the words in the sentence as a slice of string. The return value has exactly the same length as the sentence.