(subnetter) ~/src/cloudformation $ python subnetter.py
us-east-1a.admin-1: 10.0.0.0 => 10.0.0.255 (10.0.0.0/24)
us-east-1b.admin-2: 10.0.1.0 => 10.0.1.255 (10.0.1.0/24)

us-east-1.customer-foo: 10.0.2.0 => 10.0.2.63 (10.0.2.0/26)

us-east-1a.customer-foo.public-1: 10.0.2.0 => 10.0.2.7 (10.0.2.0/29)
us-east-1b.customer-foo.public-2: 10.0.2.8 => 10.0.2.15 (10.0.2.8/29)
us-east-1a.customer-foo.private-1: 10.0.2.16 => 10.0.2.31 (10.0.2.16/28)
us-east-1b.customer-foo.private-2: 10.0.2.32 => 10.0.2.47 (10.0.2.32/28)
us-east-1.customer-foo.spare: 10.0.2.48 => 10.0.2.63 (10.0.2.48/28)