code: def next(self):
          
          if not self.iter_next():
              raise StopIteration
          data = self.getdata()
          label = self.getlabel()
          # iter should stop when last batch is not complete
          if data[0].shape[0] != self.batch_size:
          # in this case, cache it for next epoch
              self._cache_data = data
              self._cache_label = label
              raise StopIteration
          return DataBatch(data=data, label=label, \
              pad=self.getpad(), index=None)
docs: Returns the next batch of data.