boto_paginate.py

def gather_pages(func, *args, **kwargs):
  result = func(*args, **kwargs)
  yield result
  while 'nextToken' in result:
    result = func(*args, kwargs, nextToken=result['nextToken'])
    yield result

def describe_all_images(registry_id, repository_name):
  client = boto3.client('ecr')
  return [image
          for image in resp['imageDetails']
          for resp in gather_pages(client.describe_images,
                                   registryId=registry_id,
                                   repositoryName=repository_name,
                                   maxResults=100)]