Hi

I have issues creating sns subscriptions through Cloudformation. If I attempt to include a `AWS::SNS::Subscription` resource in a Cloudformation template and run `create-stack` then I get a 500 Internal Server error. The full template:

```
AWSTemplateFormatVersion: '2010-09-09'
Description: 'Test'
Resources:
  MySnsTopic:
    Type: AWS::SNS::Topic
    Properties:
      TopicName: MySnsTopic
  MySnsTopicSubscription:
    Type: AWS::SNS::Subscription
    Properties:
      Protocol: sqs
      TopicArn: !Ref MySnsTopic
      Endpoint: !GetAtt
        - MySqsQueue
        - QueueArn
  MySqsQueue:
    Type: AWS::SQS::Queue
    Properties:
      QueueName: MySqsQueue
```

If I replace the references with hard-coded arns like this:

```
TopicArn: arn:aws:sns:eu-west-2:123456789012:MySnsTopic
Endpoint: arn:aws:sqs:elasticmq:000000000000:MySqsQueue
```

Then I get no errors but I get a warning:

`No moto Cloudformation support for AWS::SNS::Subscription`.

I can get around this issue by creating the subscription when creating the topic but the issue there is that I cannot add any attributes and in my case I need `RawMessageDelivery` set to true. So my questions are:

1. Is there no support to create `AWS::SNS::Subscription` resources through Cloudformation or am I doing something wrong?
2. If support is not there can I request it as a new feature?
3. Any suggestions on how I can work around this? I know I could do this through a script at startup but would like to not have any additional script steps other than deploying the Cloudformation stack.

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for t in threading.enumerate():
        print(t)
    print(run("ps aux | grep 'node\\|java\\|python'"))
def merge_recursive(source, destination):
    for key, value in source.items():
        if isinstance(value, dict):
            
            node = destination.setdefault(key, {})
            merge_recursive(value, node)
        else:
            if not isinstance(destination, dict):
                LOG.warning('Destination for merging %s=%s is not dict: %s' %
                    (key, value, destination))
            destination[key] = value
    return destination
def merge_dicts(*dicts, **kwargs):
    """ Merge all dicts in `*dicts` into a single dict, and return the result. If any of the entries
        in `*dicts` is None, and `default` is specified as keyword argument, then return `default`. """
    result = {}
    for d in dicts:
        if d is None and 'default' in kwargs:
            return kwargs['default']
        if d:
            result.update(d)
    return result
def recurse_object(obj, func, path=''):