In file binary segmentation (camvid).ipynb, block 5, there is:

# Lets look at data we have
dataset = Dataset(x_train_dir, y_train_dir, classes=['car', 'pedestrian'])
image, mask = dataset[5] # get some sample
visualize(
    image=image, 
    cars_mask=mask[..., 0].squeeze(),
    sky_mask=mask[..., 1].squeeze(),
    background_mask=mask[..., 2].squeeze(),
)

here, sky_mask

I think your install instructions are incorrect. You say pip install kerassurgeon but it should be pip install tfkerassurgeon. Also, the examples show import kerassurgeon instead of import tfkerassurgeon. The colab example seems to have it correct.