Chap 3, more clarification for Never5Classifier(BaseEstimator)

```python
from sklearn.base import BaseEstimator
class Never5Classifier(BaseEstimator):
def fit(self, X, y=None):
pass
def predict(self, X):
return np.zeros((len(X), 1), dtype=bool)
```

I don't understand how this being created. I thought it would predict not-5 class is true, but whereas `y_train[1] == 0` , `never_5_clf.predict(X_train)` is still `False` for the `[1]` ?
plz explain how this classifier work. Which code represent it can predict the not-5?