I have a LabelEncoder with 500 classes. To store and load it, I used pickle: with open('../data/label_encoder_v500.pkl', 'rb') as file: label_encoder = pickle.load(file) I want to add 24 new classes to this encoder, keeping existing labels unchanged. additional_classes = ['class501', 'class502', ..., 'class524'] It seems like this operation does not come out-of-the-box with LabelEncoder. Any help is appreciated. Continue reading...