Issues on some lines with axes and tuples:

[123raymondmok]

line 26, in
dx = np.gradient(images, axis=1).mean(axis=3)

axis = tuple([normalize_axis_index(ax, ndim, argname) for ax in axis])
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
numpy.exceptions.AxisError: axis 1 is out of bounds for array of dimension 1

[m3at]

Thanks for reporting the issue. Can you share an example of how to reproduce it?