返回嵌套字典中具有最大值的键的名称

def find_max_key(dictionary):
    max_value = float('-inf')
    max_key = None

    for key, value in dictionary.items():
        if isinstance(value, dict):  # 判断值是否为字典类型
            nested_max_key = find_max_key(value)  # 递归调用处理嵌套字典
            if nested_max_key is not None:
                if dictionary[nested_max_key] > max_value:
                    max_value = dictionary[nested_max_key]
                    max_key = nested_max_key
        else:
            if value > max_value:
                max_value = value
                max_key = key

    return max_key

# 示例嵌套字典
data = {
    'key1': {
        'subkey1': 10,
        'subkey2': 20,
        'subkey3': 30
    },
    'key2': {
        'subkey4': 40,
        'subkey5': 50,
        'subkey6': 60
    },
    'key3': {
        'subkey7': 70,
        'subkey8': 80,
        'subkey9': 90
    }
}

max_key = find_max_key(data)
print("具有最大值的键的名称是:", max_key)