# Instances of FaissIndex is essentially just a wrapper for faiss indices.
        faiss_index = cls(device=device)
        with fsspec.open(str(file), "rb", **(storage_options or {})) as f:
            index = faiss.read_index(faiss.BufferedIOReader(faiss.PyCallbackIOReader(f.read)))
        faiss_index.faiss_index = faiss_index._faiss_index_to_device(index, faiss_index.device)
        return faiss_index