Sorting fails for files with only one timestep
https://git.geomar.de/willi-rath/xorca/blob/master/xorca/lib.py#L311 returns none then.
We need to make sure to not always squeeze...
https://git.geomar.de/willi-rath/xorca/blob/master/xorca/lib.py#L311 returns none then.
We need to make sure to not always squeeze...