RuntimeError: Unknown exception at main.py line 131

[3togo]

Any pointer on how to fix it?

eli@eli-desktop:~/git/DepthFromDefocus$ python3 main.py .
INFO: Set logging level: INFO
INFO: Reading images from ./[jgptJGPT][pinPIN][gfGF]
['./Adopt-a-cat-or-kitten-from-RSPCA.jpg']
INFO: Aligning images with rigid transform.
(lx, ly)=(0 0), (rx, ry)=(800 1020)
_stack[0].shape= (1020, 800)
INFO: Generating all-in-focus image.
Traceback (most recent call last):
File "main.py", line 309, in
main(images, abs_path)
File "main.py", line 249, in main
graph_img, aif_img = all_in_focus(bw_images, unary_scale, pair_scale)
File "main.py", line 131, in all_in_focus
graph_img = cut_simple(unary.astype(np.int32),pairwise.astype(np.int32),n_iter=1)
File "gco_python.pyx", line 63, in pygco.cut_simple
RuntimeError: Unknown exception