Validate IP Address

纯模拟题，字符串的处理复杂，这里看起来IPv6的处理麻烦些，实际上还是传统的IPv4的先导零很复杂

class Solution(object):
    def validIPAddress(self, IP):
        """
        :type IP: str
        :rtype: str
        """
        if '.' in IP:
            strings = IP.split('.')
            if len(strings) != 4:
                return 'Neither'
            for string in strings:
                if not string.isnumeric():
                    return 'Neither'
                num = int(string)
                if num == 0 and len(string) > 1:
                    return 'Neither'
                if num > 0 and string[0] == '0':
                    return 'Neither'
                if num < 0 or num > 255:
                    return 'Neither'
            return 'IPv4'
        elif ':' in IP:
            strings = IP.split(':')
            if len(strings) != 8:
                return 'Neither'
            for string in strings:
                if len(string) > 4 or len(string) == 0:
                    return 'Neither'
                for char in string:
                    if char.isalpha():
                        if char.upper() not in ['A', 'B', 'C', 'D', 'E', 'F']:
                            return 'Neither'
                    elif not char.isnumeric():
                        return 'Neither'
            return 'IPv6'
        return 'Neither'