code: def get_data(self, request=None):
          
          if request is None:
              raise ValueError
          data = [[] for _ in self.sources]
          for i in range(request):
              try:
                  for source_data, example in zip(
                          data, next(self.child_epoch_iterator)):
                      source_data.append(example)
              except StopIteration:
                  # If some data has been extracted and `strict` is not set,
                  # we should spit out this data before stopping iteration.
                  if not self.strictness and data[0]:
                      break
                  elif self.strictness > 1 and data[0]:
                      raise ValueError
                  raise
          return tuple(numpy.asarray(source_data) for source_data in data)
docs: Get data from the dataset.