字典包含字典

allGuests = {
    'A':{'apples':5,'pretzels':12},
    'B':{'hs':3,'apples':2}
}
def total(guests,item):
    num = 0
    for k in guests:
        num = num +guests[k].get(item,0)
    return num
print(str(total(allGuests,'apples')))#计算字典中某个键对应的数量之和