code: def _name_to_tensor(self, tensor_name):
      
      id1, id2 = self._tensor_name_to_ids[tensor_name]
      return self._operations[id1].outputs[id2]
docs: The tensor with the given name.
  
      Args:
        tensor_name: a string, name of a tensor in the graph.
  
      Returns:
        a tf.Tensor or mtf.Tensor