please find out why an error occurs in my code

Question

sportsman = {"football": 'Messi', 'Ronaldo', "tennis": 'Federer', 'Nadal'}
print(sportsman)

Answer 1

A key can have only one value. If you have more you need to use a tuple

Answer 2

sportsman = {"football": {'Messi', 'Ronaldo'} , "tennis":{ 'Federer', 'Nadal'}}
print(sportsman)

Answer 3

Thanks