def _concat(examples: list[dict]) -> dict:
        """
        Concatenate the values of each key in the examples.

        Args:
            examples: a list of dict instances that have multiple keys
        """
        concatenated_examples = {}
        keys = examples[0].keys()
        for k in keys:
            concatenated_examples[k] = list(chain(*[e[k] for e in examples]))
        if "labels" not in keys and "input_ids" in keys:
            concatenated_examples["labels"] = concatenated_examples["input_ids"]
        return concatenated_examples

        Concatenate the values of each key in the examples.

        Args:
            examples: a list of dict instances that have multiple keys
        
smoe/data/aggregation.py