How to make old fit_generator api of keras 1.x compatible with keras 2.x

Hi, I am trying to go through cats and dogs redux python notebook. Apparently the fit_generator api for vgg16 model have changed. I ran this portion of the notebook which is -

   latest_weights_filename = None
    for epoch in range(no_of_epochs):
        print( "Running epoch: %d",  epoch), val_batches, nb_epoch=1)
        latest_weights_filename = 'ft%d.h5' % epoch
    print( "Completed %s fit operations", no_of_epochs)

It was giving me the following warning -

Running epoch: %d 0
     ../utils/ UserWarning: Update your `fit_generator` call to the Keras 2 API: `fit_generator(<keras.pre..., validation_data=<keras.pre..., steps_per_epoch=3, epochs=1, validation_steps=50)`
     Epoch 1/1
     2/3 [===================>..........] - ETA: 124s - loss: 2.4474 - acc: 0.4219

The run time is very slow , given that I am using a sample size of 200 train and 50 test images.
What changes should I make to to make it compatible to keras api 2.0.