IPv4 public subnets excluding RFC 1918

public_subnets.py

from ipaddress import ip_network

rfc_1918 = [ip_network('10.0.0.0/8'), ip_network('172.16.0.0/12'), ip_network('192.168.0.0/16')]
final = [ip_network('0.0.0.0/0')]

for ex in rfc_1918:
    for n in list(final):
        try:
            final.extend(n.address_exclude(ex))
            final.remove(n)
        except ValueError as ex:
            pass

# 0.0.0.0/5
# 8.0.0.0/7
# 11.0.0.0/8
# 12.0.0.0/6
# 16.0.0.0/4
# 32.0.0.0/3
# 64.0.0.0/2
# 128.0.0.0/3
# 160.0.0.0/5
# 168.0.0.0/6
# 172.0.0.0/12
# 172.128.0.0/9
# 172.32.0.0/11
# 172.64.0.0/10
# 173.0.0.0/8
# 174.0.0.0/7
# 176.0.0.0/4
# 192.0.0.0/9
# 192.128.0.0/11
# 192.160.0.0/13
# 192.169.0.0/16
# 192.170.0.0/15
# 192.172.0.0/14
# 192.176.0.0/12
# 192.192.0.0/10
# 193.0.0.0/8
# 194.0.0.0/7
# 196.0.0.0/6
# 200.0.0.0/5
# 208.0.0.0/4
# 224.0.0.0/3