return ds

    def _as_dataset(self, split: Union[ReadInstruction, Split] = Split.TRAIN, in_memory: bool = False) -> Dataset:
        """Constructs a `Dataset`.

        This is the internal implementation to overwrite called when user calls
        `as_dataset`. It should read the pre-processed datasets files and generate
        the `Dataset` object.

        Args:
            split (`datasets.Split`):
                which subset of the data to read.
            in_memory (`bool`, defaults to `False`):
                Whether to copy the data in-memory.