def METHOD_NAME(self, data_iter, to_gpu=True):
    """Loads a batch from data iterator. It returns the data and labels which are
    already in the same GPU as where the model's.
    Args:
        data_iter (Iterable): Data iterator from which get a batch of data, obtained by calling iter(dataloader).
        to_gpu (bool, optional): Whether the data should be moved to GPU
    Returns:
        Tuple (:class:`Tensor`, :class:`torch.Tensor`): A tuple of (data, label).
    """
    if data_iter is None:
        raise RuntimeError('Dataloader is not defined.')
    batch_data = next(data_iter)
    if to_gpu:
        batch_data = self._move_to_device(batch_data)
    self.batch_size = self._get_batch_size(batch_data)
    return batch_data