'Return a list of the images present in _base.
This method returns a dictionary with the following keys:
- unexplained_images
- originals'

def _list_datastore_images(self, ds_path, datastore):

    ds_browser = self._get_ds_browser(datastore.ref)
    originals = ds_util.get_sub_folders(self._session, ds_browser, ds_path)
    return {'unexplained_images': [], 'originals': originals}
