def _remove_unused_ops(self, control_inputs=True): """Remove unused ops in place. Args: control_inputs: if True, control inputs are used to detect used ops. Returns: A new subgraph view which only contains used operations. """ ops = select.get_walks_union_ops(self.connected_inputs, self.connected_outputs, within_ops=self._ops, control_inputs=control_inputs) self._ops = [op for op in self._ops if op in ops]