'Remove the async SNS topic.'

def remove_async_sns_topic(self, lambda_name):

    topic_name = get_topic_name(lambda_name)
    removed_arns = []
    for sub in self.sns_client.list_subscriptions()['Subscriptions']:
        if (topic_name in sub['TopicArn']):
            self.sns_client.delete_topic(TopicArn=sub['TopicArn'])
            removed_arns.append(sub['TopicArn'])
    return removed_arns
