code: def _collate(self, batch):
          
  
          if isinstance(batch[0], tuple):
              return [self._cuda(torch.Tensor(samples)) for samples in list(zip(*batch))]
          else:
              return self._cuda(torch.Tensor(batch))
docs: Puts each data field into a tensor.
  
          :param batch: The input data batch.
          :type batch: list of features
          :return: Preprocessed data.
          :rtype: torch.Tensor or pair of torch.Tensor