minify a list of CIDrs to the largest CID listed

minimal_cidr_list.py

#!/usr/bin/env python

import sys
from ipaddress import IPv4Network
from collections import defaultdict

if __name__ == "__main__":
    inputs = defaultdict(list)
    for line in sys.stdin:
        cidr = line.strip().decode('utf-8')
        if not cidr:
            continue
        net = IPv4Network(cidr)
        inputs[net.prefixlen].append(net)
    c = []
    for i in range(10, 25):
        for net in inputs[i]:
            found = False
            for n in c:
                if net.subnet_of(n):
                    found=True
                    break
            if not found:
                c.append(net)
    for x in c:
        print str(x)