检索类实例中的嵌套字典

class NestedDictExample:
    def __init__(self):
        self.data = {
            'name': 'John',
            'age': 30,
            'contact': {
                'email': 'john@example.com',
                'phone': '1234567890'
            },
            'address': {
                'street': '123 Street',
                'city': 'New York',
                'state': 'NY'
            }
        }

    def get_value(self, keys):
        nested_dict = self.data
        for key in keys:
            if isinstance(nested_dict, dict) and key in nested_dict:
                nested_dict = nested_dict[key]
            else:
                return None
        return nested_dict

# 创建类实例
example = NestedDictExample()

# 从嵌套字典中检索数据
name = example.get_value(['name'])
email = example.get_value(['contact', 'email'])
city = example.get_value(['address', 'city'])

print(name)   # 输出：John
print(email)  # 输出：john@example.com
print(city)   # 输出：New York