Is this what you are trying to accomplish?

$ python
Python 2.7.15rc1 (default, Nov 12 2018, 14:31:15)
[GCC 7.3.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> import netaddr
>>> SomeList=netaddr.IPSet()
>>> SomeList.add('203.0.113.0/25')
>>> SomeList.add('203.0.113.128/25')
>>> for x in list(SomeList.iter_cidrs()):
... print x
...
203.0.113.0/24

>>>
>>> DifferentList=netaddr.IPSet()
>>> DifferentList.add('0.0.0.0/0')
>>> DifferentList.remove('203.0.113.1')
>>> for x in list(DifferentList.iter_cidrs()):
... print x
...
0.0.0.0/1
128.0.0.0/2
192.0.0.0/5
200.0.0.0/7
202.0.0.0/8
203.0.0.0/18
203.0.64.0/19
203.0.96.0/20
203.0.112.0/24
203.0.113.0/32
203.0.113.2/31
203.0.113.4/30
203.0.113.8/29
203.0.113.16/28
203.0.113.32/27
203.0.113.64/26
203.0.113.128/25
203.0.114.0/23
203.0.116.0/22
203.0.120.0/21
203.0.128.0/17
203.1.0.0/16
203.2.0.0/15
203.4.0.0/14
203.8.0.0/13
203.16.0.0/12
203.32.0.0/11
203.64.0.0/10
203.128.0.0/9
204.0.0.0/6
208.0.0.0/4
224.0.0.0/3
>>>

On Sun, Oct 27, 2019 at 1:10 PM Joe Maimon <jmaimon@jmaimon.com> wrote:

Does anyone have or seen any such tool? I have a script that seems to
work, but its terribly slow.

Currently I can produce aggregated subnets that can be mising up to a
specified number of individual addresses. Which can be fed back in for
multiple passes.

Doing RTBH on individual /32 does not scale well, if you are eyeing
collaboration with external lists. I have found likely sources that could
produce another 100k prefixes easily.

Joe