from netaddr import *
import boto3

'''
you will need the following pips:
netaddr
boto3
'''

AK=''
SK=''

inputs = [['us-west-2', 'vpc-7155ca14'],['eu-west-1','vpc-55a5a930']]

for v1 in inputs:
    session = boto3.Session(
        aws_access_key_id=AK,
        aws_secret_access_key=SK,
        region_name=v1[0]
    )

    ec2 = session.resource('ec2')
    vpc = ec2.Vpc(v1[1])
    subnets = []
    for subnet in vpc.subnets.all():
        subnets.append(IPNetwork(subnet.cidr_block))

    lastSubnet = sorted(subnets).pop()
    print (v1[0], 'next subnet:', lastSubnet.next())