src/transformers/models/rag/retrieval_rag.py/HFIndexBase/__init__
class HFIndexBase:    def __init__(self, vector_size, dataset, index_initialized=False):
        self.vector_size = vector_size
        self.dataset = dataset
        self._index_initialized = index_initialized
        self._check_dataset_format(with_index=index_initialized)
        dataset.set_format("numpy", columns=["embeddings"], output_all_columns=True, dtype="float32")