cities_dict={'Beijing': {'Capital': 'China'}, 'Moscow': {'Capital': 'Russia'}, 'Paris': {'Capital': 'France'}}
for i in sorted(cities_dict):
    for j in sorted(cities_dict[i]):
        print(f'{i} is the capital of {cities_dict[i][j]}!')
字典中嵌套字典，把握好各层次关系就行。