func IsIPv4(s string) bool {
	ip := net.ParseIP(s)
	return ip != nil
}
func IsIPv4(s string) bool {
	ip := net.ParseIP(s)
	return ip != nil
}
func IsIPv4 ( s string ) bool { ip := net . ParseIP ( s ) return ip != nil }
// IsIPv4 checks if this is a valid IPv4
IsIPv4 checks if this is a valid IPv4