Typo in exercise 2 chapter 8 ?

Typo in exercise 2 chapter 8 ?

par Adrien Shun Pierre Vauthey,
Nombre de réponses : 0
In the example, shouldn't it be : sum_per_row = np.sum(a, axis=1) instead of sum_per_row = np.mean(a, axis=1) ?
Same for columns