code: func extractTag(key string, lines []string) string {
  	val, present := types.ExtractCommentTags("+", lines)[key]
  	if !present || len(val) < 1 {
  		return ""
  	}
  
  	return val[0]
  }
docs: // extractTag gets the comment-tags for the key.  If the tag did not exist, it
  // returns the empty string.