多层字典访问
首都
https://www.nowcoder.com/practice/03a5031ed7ad4a7db897fd9ed982ea57
cities_dict = {'Beijing': {'Capital': 'China'}, 'Moscow': {'Capital': 'Russia'}, 'Paris': {'Capital': 'France'}}
for key in sorted(cities_dict.keys()):
print('%s is the capital of %s!'%(key, cities_dict[key]['Capital']))
