sequenceDiagram
    participant Pydantic as Pydantic Model
    participant DataDict
    participant Django as Django Model
    participant DB as Database

    Pydantic->>DataDict: ddict_class returns type
    Pydantic->>Pydantic: model_dump() → dict
    Pydantic->>DataDict: validate(dumped_dict)
    DataDict-->>Pydantic: ✓ DataDict instance
    
    DataDict->>Django: sync_from_ddict(ddict)
    Django->>Django: parse nested fields
    Django->>Django: resolve FK by name
    Django->>Django: update_or_create(pk=uuid)
    Django->>DB: INSERT/UPDATE
    DB-->>Django: ✓ persisted
    Django-->>Django: refresh_from_db()
    
    Django->>Pydantic: model_validate(Django.ddict)
    Pydantic->>Pydantic: deserialize to Pydantic
    Pydantic-->>Django: ✓ round-trip complete