List all EC2 instances in a region

instance-types.py

#!/usr/bin/env python

import boto3

ec2 = boto3.client('ec2', region_name='us-east-1')

instance_types = [] 

types = ec2.describe_instance_types()
instance_types.extend(types['InstanceTypes'])

next_token = ''
if 'NextToken' in types:
    next_token = types['NextToken']

    while next_token != '':
        types = ec2.describe_instance_types(NextToken=next_token)
        instance_types.extend(types['InstanceTypes'])

        if 'NextToken' in types:
            next_token = types['NextToken']
        else:
            next_token = ''

for i in instance_types:
    print(i['InstanceType'])