将嵌套字典的结果相加在一起

nested_dict = {
    'a': {'x': 1, 'y': 2},
    'b': {'x': 3, 'y': 4},
    'c': {'x': 5, 'y': 6}
}

result = 0
for key in nested_dict:
    result += sum(nested_dict[key].values())

print(result)

21