code: func queryBool(q url.Values, key string) bool {
  	if _, ok := q[key]; !ok {
  		return false
  	}
  
  	return q.Get(key) != "false"
  }
docs: // queryBool returns the query parameter parsed as a boolean. An empty value
  // ("?foo") is considered true, as is any value string except false
  // ("?foo=false").