###newbie exact answer desired (Python v3):
###=================================
"""
cars = {'A':{'speed':70,
'color':2},
'B':{'speed':60,
'color':3}}
"""
for keys, values in reversed(sorted(cars.items())):
print(keys)
for keys,values in sorted(values.items()):
print(keys," : ", values)
"""
Output:
B
color : 3
speed : 60
A
color : 2
speed : 70
##[Finished in 0.073s]
"""