docs: def _build(self):
      """Connects the TrainableTensor module into the graph.
  
      Returns:
        A Tensor of shape as determined in the constructor.
      """
      if "w" not in self._initializers:
        stddev = 1 / math.sqrt(np.prod(self._shape))
        self._initializers["w"] = tf.truncated_normal_initializer(stddev=stddev)
  
      self._w = tf.get_variable("w",
                                shape=self._shape,
                                dtype=self._dtype,
                                initializer=self._initializers["w"],
                                partitioner=self._partitioners.get("w", None),
                                regularizer=self._regularizers.get("w", None))
      return self._w