def _get_objective_info(num_classes):
    """Provide information on classifier objective.

    :param num_classes: integer greater than 1; number of classes
    :return: dict with information on objective and evaluation metric for XGBoost
    """
    if num_classes == 2:
        return {"objective": "binary:logistic", "eval_metric": "logloss"}
    return {"objective": "multi:softprob", "eval_metric": "mlogloss", "num_class": num_classes}