Error creating a ModelSingleton record

At create a Singleton record, this is created and updated with the same data.

In my Singleton only have a o2m with a field required and unique in target. For this, is impossible create the record because the linked write method, the create call, and super().write contains the same data: 'o2m_field': [['create', [{'field1': 'foo', 'user': 1}]]]

As one of the O2M fields is unique, do not allow save/create