<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def delete(self, *args, **kwargs):
 """Delete the data model."""

        # Store ids in memory as relations are also deleted with the Data object.
        storage_ids = list(self.storages.values_list('pk', flat=True))  # pylint: disable=no-member

        super().delete(*args, **kwargs)

        Storage.objects.filter(pk__in=storage_ids, data=None).delete()