Thilo Balke

First, let's have a type, i.e. `ScicoArray = Union[BlockArray, DeviceArray]` or whatever we want to call it. I think there are arrays that don't make sense to be `ScicoArray`s. For...

In general, it often happens that `None` is passed as an argument as in ```python kwargs = {'positivity': True} ... recon( ... positivity=kwargs.get('positivity'), # returns True max_iterations=kwargs.get('max_iterations'), # returns `None`...