I am using the **latest** localstack docker image to test aws s3, lambda and cloudformation locally. s3 and lambda seems to be working fine but when I call cloudformation **create-stack** api it gives me a 502 BadGateway error. This is the command I am using

`aws cloudformation create-stack \
  --template-body template.yaml \
  --stack-name cfn-test \
  --parameters ParameterKey=BucketPrefix,ParameterValue=demo-bucket \
  --endpoint-url=http://localhost:4581`

This is the error I get:
`An error occurred (502) when calling the CreateStack operation (reached max retries: 4): Bad Gateway`

From docker logs I got the following error
`2019-12-31T22:12:09:ERROR:localstack.services.generic_proxy: Error forwarding request: 'str' object has no attribute 'get' Traceback (most recent call last):
  File "/opt/code/localstack/localstack/services/generic_proxy.py", line 242, in forward
    path=path, data=data, headers=forward_headers)
  File "/opt/code/localstack/localstack/services/cloudformation/cloudformation_listener.py", line 164, in forward_request
    modified_request = transform_template(req_data)
  File "/opt/code/localstack/localstack/services/cloudformation/cloudformation_listener.py", line 83, in transform_template
    if parsed.get('Transform') == 'AWS::Serverless-2016-10-31':
AttributeError: 'str' object has no attribute 'get'`

Although, when I try the **list-stacks** api it seems to be working fine
`aws --endpoint-url=http://localhost:4581 cloudformation list-stacks`

`{
    "StackSummaries": []
}`

`2019-12-31 22:10:51,865:API: 127.0.0.1 - - [31/Dec/2019 22:10:51] "GET / HTTP/1.1" 200 -`

I could not find a solution in any of the past issues or anywhere on the internet. Please assist
raise MalformedXML()
        deleted_names = []
        error_names = []
        keys = []
        for element in elements:
            if len(element.getElementsByTagName('VersionId')) == 0:
                version_id = None
            else:
                version_id = element.getElementsByTagName('VersionId')[0].firstChild.nodeValue
            keys.append({
                'key_name': element.getElementsByTagName('Key')[0].firstChild.nodeValue,
                'version_id': version_id
            })
        for k in keys:
            key_name = k['key_name']
            version_id = k['version_id']
            success = self.backend.delete_key(
                bucket_name, undo_clean_key_name(key_name), version_id)
            if success:
                deleted_names.append({
                    'key': key_name,
                    'version_id': version_id
                })
            else:
                error_names.append(key_name)
        return (200, {},
            template.render(deleted=deleted_names, delete_errors=error_names))
    s3_responses.S3ResponseInstance._bucket_response_delete_keys = types.MethodType(
        s3_bucket_response_delete_keys, s3_responses.S3ResponseInstance)