src/transformers/data/processors/squad.py/SquadProcessor/get_train_examples
class SquadProcessor:    def get_train_examples(self, data_dir, filename=None):
        """
        Returns the training examples from the data directory.

        Args:
            data_dir: Directory containing the data files used for training and evaluating.
            filename: None by default, specify this if the training file has a different name than the original one
                which is `train-v1.1.json` and `train-v2.0.json` for squad versions 1.1 and 2.0 respectively.

        """
        if data_dir is None:
            data_dir = ""

        if self.train_file is None:
            raise ValueError("SquadProcessor should be instantiated via SquadV1Processor or SquadV2Processor")

        with open(
            os.path.join(data_dir, self.train_file if filename is None else filename), "r", encoding="utf-8"
        ) as reader:
            input_data = json.load(reader)["data"]
        return self._create_examples(input_data, "train")