Warm-Up

An IP address is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication. There are two versions of the Internet protocol, and thus two versions of addresses. One of them is the IPv4 address.

IPv4 addresses are represented in dot-decimal notation, which consists of four decimal numbers, each ranging from 0 to 255, separated by dots, e.g., 172.16.254.1

Given a string, write a function that determines whether it is a valid IP address.