code: func (wl *Basic) Permitted(ip net.IP) bool {
  	if !validIP(ip) {
  		return false
  	}
  
  	wl.lock.Lock()
  	permitted := wl.whitelist[ip.String()]
  	wl.lock.Unlock()
  	return permitted
  }
docs: // Permitted returns true if the IP has been whitelisted.