Michael Kuron authored 4 years ago and Markus Holzer committed 4 years ago

and clean up some old xfails

Stephan Seitz authored 4 years ago and Markus Holzer committed 4 years ago

We have to try from newest to oldest import to avoid deprecation
warnings.

Frederik Hennig authored 4 years ago and Markus Holzer committed 4 years ago

- `shift_slice` did not work for single slices as it always tried to
iterate its argument
- `shift_slice` returned lists of slices, but for accessing numpy
arrays, tuples of slices are required