Example:
```python
>>> from huggingface_hub import SpaceCardData
>>> card_data = SpaceCardData(
...     title="Dreambooth Training",
...     license="mit",
...     sdk="gradio",
...     duplicated_from="multimodalart/dreambooth-training"
... )
>>> card_data.to_dict()
{'title': 'Dreambooth Training', 'sdk': 'gradio', 'license': 'mit', 'duplicated_from': 'multimodalart/dreambooth-training'}
```
```