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

def _name_to_tensor(self, tensor_name):
    """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
    """
    id1, id2 = self._tensor_name_to_ids[tensor_name]
    return self._operations[id1].outputs[id2]