Draft: Fix sino normalization

This MR fixes the following piece of code (reported as error by pylint):

                intensities = DataUrl(path=kwargs["dataset_url"])
                if intensities is None:
                    raise ValueError("No dataset for intensity monitoring found")
                else:
                    i_values = set(intensities.values())
                    if len(i_values) == 1 and list(i_values)[0] is None:
                        raise ValueError("No dataset for intensity monitoring found")

                    intensities = [
                        intensities[key] for key in sorted(intensities.keys())
                    ]