'Remove the object_store/file for this dataset from storage and mark
as purged.
:raises exceptions.ConfigDoesNotAllowException: if the instance doesn\'t allow'

def purge(self, dataset, flush=True):

    self.error_unless_dataset_purge_allowed(dataset)
    dataset.full_delete()
    self.session().add(dataset)
    if flush:
        self.session().flush()
    return dataset
