Reset the batch of environments.

    Args:
      indices: The batch indices of the environments to reset; defaults to all.

    Returns:
      Batch tensor of the new observations.

def _reset_non_empty(self, indices):
    """Reset the batch of environments.

    Args:
      indices: The batch indices of the environments to reset; defaults to all.

    Returns:
      Batch tensor of the new observations.
    """
    observ = tf.py_func(
        self._batch_env.reset, [indices], self.observ_dtype, name="reset")
    observ.set_shape(indices.get_shape().concatenate(self.observ_shape))
    with tf.control_dependencies([
        tf.scatter_update(self._observ, indices, observ)]):
      return tf.identity(observ)