When a subscription is created using cloudformation:
```
"ProfileChangedSubscription": {
      "Type": "AWS::SNS::Subscription",
      "Properties": {
        "Endpoint": {
          "Fn::GetAtt": [
            "ProfileChangedQueue",
            "Arn"
          ]
        },
        "Protocol": "sqs",
        "FilterPolicy": {
          "eventType": [
            "created"
          ]
        },
        "TopicArn": {
          "Fn::ImportValue": {
            "Fn::Sub": "${ProfilesProfilePublishStack}-ProfileChangedTopic"
          }
        }
      }
    }
```

The specified subscription filter policy is not created. When I run `get-subscription-attributes`, I get information about non-existing filter policy:

```
{
    "Attributes": {
        "TopicArn": "arn:aws:sns:us-east-1:000000000000:profile-changed-topic",
        "Endpoint": "arn:aws:sqs:us-east-1:000000000000:profile-changed-queue",
        "Protocol": "sqs",
        "SubscriptionArn": "arn:aws:sns:us-east-1:000000000000:profile-changed-topic:936a58be-525b-4228-bfdb-c4b2f6048e8c",
        "FilterPolicy": "None"
    }
}
```
""" Convert a CloudFormation ACL string (e.g., 'PublicRead') to an S3 ACL string (e.g., 'public-read') """
    return re.sub('(?<!^)(?=[A-Z])', '-', acl).lower()
def retrieve_topic_arn(topic_name):
    topics = aws_stack.connect_to_service('sns').list_topics()['Topics']
    topic_arns = [t['TopicArn'] for t in topics if t['TopicArn'].endswith(':%s' % topic_name)]
    return topic_arns[0]
def get_role_arn(role_arn, **kwargs):
    role_arn = resolve_refs_recursively(kwargs.get('stack_name'), role_arn, kwargs.get('resources'))
    return aws_stack.role_arn(role_arn)
def parse_template(template):
    try:
        return json.loads(template)
    except Exception:
        yaml.add_multi_constructor('', moto.cloudformation.utils.yaml_tag_constructor, Loader=NoDatesSafeLoader)
        try:
            return yaml.safe_load(template)
        except Exception:
            return yaml.load(template, Loader=NoDatesSafeLoader)
def template_to_json(template):
    template = parse_template(template)
    return json.dumps(template)
def get_resource_type(resource):
    res_type = resource.get('ResourceType') or resource.get('Type') or ''
    parts = res_type.split('::', 1)
    if len(parts) == 1:
        return None
    return parts[1]
def get_service_name(resource):