Example:

        ```python
        >>> ds = datasets.load_dataset('crime_and_punish', split='train')
        >>> ds_with_embeddings = ds.map(lambda example: {'embeddings': embed(example['line']}))
        >>> ds_with_embeddings.add_faiss_index(column='embeddings')
        >>> # query
        >>> scores, retrieved_examples = ds_with_embeddings.get_nearest_examples('embeddings', embed('my new query'), k=10)
        >>> # save index
        >>> ds_with_embeddings.save_faiss_index('embeddings', 'my_index.faiss')