python用户交互，显示省市县三级联动的选择

dic = {"河北":
           {"石家庄": ["鹿泉", "藁城", "元氏"],
            "邯郸": ["永年", "涉县", "磁县"]},
       "河南":{'郑州':['A1','B2','C3']},
       "山西":{'大同':['灵丘','广灵','浑源'],
             '太原':['小店区','迎泽区']}
            }
for m in dic:
     print(m)
mbl = input ("Please your dizhi:")
for b in dic[mbl]:
     print(b)
mbl1 = input("please your dizhi")
for l in dic[mbl][mbl1]:
     print(l)