python:如何在包含列表列表的字典中查找索引

def find_index_in_dict(dictionary, target):
    for key, value in dictionary.items():
        if isinstance(value, list):
            for i, item in enumerate(value):
                if isinstance(item, list):
                    try:
                        index = item.index(target)
                        return index
                    except ValueError:
                        continue
    return -1

my_dict = {
    'key1': [1, 2, 3],
    'key2': [[4, 5, 6], [7, 8, 9]],
    'key3': [10, 11, 12]
}

target = 7
index = find_index_in_dict(my_dict, target)
print(index)  # 输出：1