area ={'世界':{'中国':{'广东':{'佛山':{'南海':{'桂城':'我家'}},'广州':{'荔湾':None}},'香港':{'九龙':None}},'美国':{}}}defprint_k(area, i=0):for k in area:print('----'* i, k, sep='')ifisinstance(area[k],dict):
print_k(area[k], i+1)
print_k(area)
dt ={'collect':'Apple','next':{'other':'nothing','collect':'Ball','next':{'collect':'Cat','next':None}}}defcollect(dt, ls=[]):for k in dt:if k =='collect':
ls.append(dt[k])elif k =='next':ifisinstance(dt[k],dict):return collect(dt[k], ls)else:return ls
print(collect(dt))