Boto（Python）：检查SQS>SNS订阅

Question

我有一个SNS-arn和一个SQS-arn。我想查一下这两者之间是否有订阅。我现在唯一可以这样做的方法是像这样暴力地强制订阅列表：

    result =  self.connection.get_all_subscriptions_by_topic(sns_arn)
    if (result and result['ListSubscriptionsByTopicResponse'] 
        and result['ListSubscriptionsByTopicResponse']
        and result['ListSubscriptionsByTopicResponse']['ListSubscriptionsByTopicResult']):
        subscriptions = result['ListSubscriptionsByTopicResponse']['ListSubscriptionsByTopicResult']['Subscriptions']
        for subscription in subscriptions:
            if (subscription['Protocol'] == type and subscription['Endpoint'] == sqs_arn and subscription['SubscriptionArn']):
                return subscription['SubscriptionArn']
    return None

我能做得更好吗？在