docs: def _unpack_dict(example):
      """
      Input data format standardization
      """
      try:
          x = example['data']
          y = example['target']
          meta = example.get('metadata', {})
          return x, y, meta
      except KeyError:
          raise IndicoError(
              "Invalid input data.  Please ensure input data is "
              "formatted as a list of dicts with `data` and `target` keys. "
              "A `metadata` key may optionally be included."
          )