Chapter 3 (Page 82): Getting error during Fitting the SGD Classifier with Training data

**I getting errors for these lines of codes:**

from sklearn.linear_model import SGDClassifier
y_train_5 = (y_train == 5)
y_test_5 = (y_test == 5)
sgd_clf = SGDClassifier(max_iter=5, tol=1e-3, random_state=42)
sgd_clf.fit(X_train, y_train_5)

****ValueError:** The number of classes has to be greater than one; got 1 class**

How can I solve this issue? Please guide me. Thank you so much.