Problem
Develop a Python function to check whether a given string is a valid IPV4 address.
Recall: IPV4 addresses contain only the numbers 0 to 255 in groups of 4 and are separated by the '.' character. For example: 127.0.0.1, 192.168.199.212, and 8.8.8.8 are all valid addresses, but 127.9.1, 333.121.0.0, 121.22.33.44.55 are not.
The function prototype MUST be: def validateIP(addr): and returns true if the IP address is valid or false otherwise.