def classification (batch_size = 20, epochs = 20, img_width = 150,
                    img_height = 150, num_train_samples = 2000, 
                    num_validation_samples = 800, learning_rate=0.001):
    model.compile(loss='binary_crossentropy',
                  optimizer=optimizers.RMSprop(learning_rate),
                  metrics=['accuracy'])
    etc.
