def flatten_indices(
        self,
        keep_in_memory: bool = False,
        cache_file_names: Optional[Dict[str, Optional[str]]] = None,
        writer_batch_size: Optional[int] = 1000,
        features: Optional[Features] = None,
        disable_nullable: bool = False,
        num_proc: Optional[int] = None,
        new_fingerprint: Optional[str] = None,
    ) -> "DatasetDict":
        """Create and cache a new Dataset by flattening the indices mapping.