return "";
    }
    *impl()->scope_used_ = true;
    return impl()->op_name_;
  }
  return impl()->op_name_.empty() ? impl()->GetNameForOp(default_name)
                                  : impl()->GetNameForOp(impl()->op_name_);
}

Scope Scope::NewSubScope(const string& child_scope_name) const {
  if (child_scope_name.empty()) {

      const Operation& colocate_with_op) const;

  // Helper functions to get a unique names.
  string GetUniqueName(const string& prefix, bool check_single_use) const;
  string GetNameForOp(const string& default_name) const;

  bool single_use_scope() const { return scope_used_ != nullptr; }

  // The graph, status, and name maps are shared by all child scopes

    .SetIsAggregate();

Node* Sequencer(const GraphDefBuilder::Options& opts,
                const string& call_node_name) {
  if (opts.HaveError()) return nullptr;
  NodeBuilder node_builder(opts.GetNameForOp("NoOp"), "NoOp",
                           opts.op_registry());
  return opts.WithAttr(kXlaHostTransferSequencerAttr, call_node_name)
      .FinalizeBuilder(&node_builder);
}

  // Don't set any value field in the proto, since it is only going to be used
  // for shape inference.

  GraphDefBuilder::Options options(graph_out, /*status=*/nullptr);
  NodeBuilder node_builder(options.GetNameForOp("KnownShape"), "Const",
                           options.op_registry());
  node_builder.Attr("dtype", data_type).Attr("value", dummy_proto);
  Node* node = options.FinalizeBuilder(&node_builder);