undo changes from 95147087104c92a011675c280aa6780ad2e5fe86 (da.concatenate instead of np.concatenate) that don't seem to work for newer verstions of dask.
undo changes from 95147087104c92a011675c280aa6780ad2e5fe86 (da.concatenate instead of np.concatenate) that don't seem to work for newer verstions of dask.

RealPolitiX/mpes