There is an error in the Capstone Project Code ('Section #4 - Capstone/simpsons.ipynb'). x_train, x_val, y_train, y_val = caer.train_test_split(featureSet, labels, val_ratio=.2) This should be x_train, x_val, y_train, y_val = caer.train_val_split(featureSet, labels, val_ratio=.2)