while developing on localstack found out that the python version used is 2.7, while the docker-image uses version 3.6.8

as in the readme file I brought up my environment using:
```
make install
make infra
```
this will cause issues when touching parts different in these 2 major versions.

workaround:
```
make reinstall-p3
```
this changed the python version to 3.7.3 on debian 10, which is again above docker-image version...
global SEQUENCE_NUMBER_COUNTER
    kinesis = aws_stack.connect_to_service('kinesis')
    for record in records:
        if 'SequenceNumber' not in record['dynamodb']:
            record['dynamodb']['SequenceNumber'] = str(SEQUENCE_NUMBER_COUNTER)
            SEQUENCE_NUMBER_COUNTER += 1
        table_arn = record['eventSourceARN']
        stream = DDB_STREAMS.get(table_arn)
        if stream:
            table_name = table_name_from_stream_arn(stream['StreamArn'])
            stream_name = get_kinesis_stream_name(table_name)
            kinesis.put_record(StreamName=stream_name, Data=json.dumps(record), PartitionKey='TODO')
@app.route('/', methods=['POST'])
def post_request():
    action = request.headers.get('x-amz-target')
    data = json.loads(to_str(request.data))
    result = {}
    kinesis = aws_stack.connect_to_service('kinesis')
    if action == '%s.ListStreams' % ACTION_HEADER_PREFIX:
        result = {
            'Streams': list(DDB_STREAMS.values()),
            'LastEvaluatedStreamArn': 'TODO'
        }
    elif action == '%s.DescribeStream' % ACTION_HEADER_PREFIX:
        for stream in DDB_STREAMS.values():
            if stream['StreamArn'] == data['StreamArn']:
                result = {
                    'StreamDescription': stream
                }