def _test_neptune_saver_integration(device):

    model = torch.nn.Module().to(device)
    to_save_serializable = {"model": model}

    mock_logger = None
    if idist.get_rank() == 0:
        mock_logger = MagicMock(spec=NeptuneLogger)
        mock_logger.log_artifact = MagicMock()
        mock_logger.delete_artifacts = MagicMock()

    saver = NeptuneSaver(mock_logger)

    checkpoint = Checkpoint(to_save=to_save_serializable,
                            save_handler=saver,
                            n_saved=1)

    trainer = Engine(lambda e, b: None)
    trainer.state = State(epoch=0, iteration=0)
    checkpoint(trainer)
    trainer.state.iteration = 1
    checkpoint(trainer)
    if idist.get_rank() == 0:
        assert mock_logger.log_artifact.call_count == 2
        assert mock_logger.delete_artifacts.call_count == 1
def resume_from(
    to_load: Mapping,
    checkpoint_fp: Union[str, Path],
    logger: Logger,
    strict: bool = True,
    model_dir: Optional[str] = None,
) -> None:
    """Loads state dict from a checkpoint file to resume the training.

    Parameters
    ----------
    to_load
        a dictionary with objects, e.g. {“model”: model, “optimizer”: optimizer, ...}
    checkpoint_fp
        path to the checkpoint file
    logger
        to log info about resuming from a checkpoint
    strict
        whether to strictly enforce that the keys in `state_dict` match the keys
        returned by this module’s `state_dict()` function. Default: True
    model_dir
        directory in which to save the object
    """
    if isinstance(checkpoint_fp, str) and checkpoint_fp.startswith("https://"):
        checkpoint = torch.hub.load_state_dict_from_url(
            checkpoint_fp, model_dir=model_dir, map_location="cpu", check_hash=True
        )
    else:
        if isinstance(checkpoint_fp, str):
            checkpoint_fp = Path(checkpoint_fp)

        if not checkpoint_fp.exists():
            raise FileNotFoundError(f"Given {str(checkpoint_fp)} does not exist.")
        checkpoint = torch.load(checkpoint_fp, map_location="cpu")

    Checkpoint.load_objects(to_load=to_load, checkpoint=checkpoint, strict=strict)
    logger.info("Successfully resumed from a checkpoint: %s", checkpoint_fp)