test_valid_ipv4.py

#A valid IPv4 address is a string that contains 
# four decimal numbers separated by periods, 
# where each decimal number is between 0 and 255.

def is_valid_IPv4(ip_address):
    # Split the IP address string into a list of 4 decimal numbers
    parts = ip_address.split(".")

    # Check that there are exactly 4 parts
    if len(parts) != 4:
        return False

    # Check that each part is an integer between 0 and 255
    for part in parts:
        try:
            # Convert each part to an integer
            num = int(part)
        except ValueError:
            # If a part cannot be converted to an integer, the address is not valid
            return False

        # Check that the integer is between 0 and 255
        if num < 0 or num > 255:
            return False

    # If all checks pass, the address is valid
    return True