def _split_generators(self, dl_manager):
        if not self.config.data_files:
            raise ValueError(f"At least one data file must be specified, but got data_files={self.config.data_files}")
        dl_manager.download_config.extract_on_the_fly = True
        # Do an early pass if:
        # * `drop_labels` is None (default) or False, to infer the class labels
        # * `drop_metadata` is None (default) or False, to find the metadata files
        do_analyze = not self.config.drop_labels or not self.config.drop_metadata
        labels, path_depths = set(), set()
        metadata_files = collections.defaultdict(set)