python nullable数组访问成语？

Question

我需要访问一些嵌套结构，例如

zip = data['customer']['primary_contact']['address']['zip']

在其中一些可能为空（无）的情况下，有没有比编写更方便的方法

zip = None
if(not(data['customer'] is None)):
    if(not(data['customer']['primary_contact'] is None)):
        if(not(data['customer']['primary_contact']['address'] is None)):
            zip = data['customer']['primary_contact']['address']['zip']