def METHOD_NAME(self, dataset, dataset_info):
    """Update dataset attributes."""
    dataset.attrs.update(self[dataset_info['nc_key']].attrs)
    dataset.attrs.update(dataset_info)
    dataset.attrs['sensor'] = 'merged'
    dataset.attrs['composite_period'] = self.composite_period
    # remove attributes from original file which don't apply anymore
    dataset.attrs.pop("nc_key")