Изменения

y_train_pred = cross_val_predict(sgd_clf, X_train, y_train_5, cv=3)

print(confusion_matrix(y_train_5, y_train_pred))

# [ 1891, 3530]])

y_train_perfect_predictions = y_train_5 # притворись, что мы достигли совершенства

print(confusion_matrix(y_train_5, y_train_perfect_predictions))

# [ 0, 5421]])