def METHOD_NAME():
    argument_spec = dict(
        topic_arn=dict(type="str", required=False),
    )
    module = AnsibleAWSModule(argument_spec=argument_spec, supports_check_mode=True)
    topic_arn = module.params.get("topic_arn")
    try:
        connection = module.client("sns", retry_decorator=AWSRetry.jittered_backoff())
    except (botocore.exceptions.ClientError, botocore.exceptions.BotoCoreError) as e:
        module.fail_json_aws(e, msg="Failed to connect to AWS.")
    if topic_arn:
        results = dict(sns_arn=topic_arn, sns_topic=get_info(connection, module, topic_arn))
    else:
        results = list_topics(connection, module)
    module.exit_json(result=results)