code: func ParseCIDR(s string) (*net.IPNet, error) {
  	ip, ipn, err := net.ParseCIDR(s)
  	if err != nil {
  		return nil, err
  	}
  
  	ipn.IP = ip
  	return ipn, nil
  }
docs: // ParseCIDR takes a string like "10.2.3.1/24" and
  // return IPNet with "10.2.3.1" and /24 mask