code: def _next(self):
      self.next_index += 1
      if isinstance(self.x, tf.data.Dataset):
          return next(self.x_iter)
      else:
          return next(self.x_iter), next(self.y_iter)
  
file_path: BigDL/python/nano/src/bigdl/nano/deps/openvino/tf/dataloader.py
imports: from openvino.tools.pot import DataLoader
  import tensorflow
  from bigdl.nano.utils.common import invalidInputError
label_desc: Use image node_id 5 for calling the KerasOpenVINODataLoader obj's underlying member method code with example usage: obj._next() and returns: next, next,  next