Class Callback

tests/python/test_basic.py:253–263

        # Use callback to log the test labels in each fold
        class Callback(xgb.callback.TrainingCallback):
            def __init__(self) -> None:
                super().__init__()

            def after_iteration(
                self,
                model,
                epoch: int,
                evals_log: xgb.callback.TrainingCallback.EvalsLog,
            ):
                print([fold.dtest.get_label() for fold in model.cvfolds])

        cb = Callback()