Node* s1 = Sequencer(
        b2.opts().WithName("F1_sequencer").WithControlInputs({recv1, send1}),
        "F1");

    NodeBuilder node_builder1("F1", "F1", lib_def.get());
    node_builder1.Input(a).Input(b);
    Node* call1 =
        b2.opts().WithControlInputs({s1, b}).FinalizeBuilder(&node_builder1);

    Node* key_constant2 =
        KeyPlaceholder("F2", b2.opts().WithName("F2_key_placeholder"));

  Node* ret = nullptr;

  if (desc->graph->name_map.count(desc->node_builder.node_name())) {
    status->status = InvalidArgument("Duplicate node name in graph: '",
                                     desc->node_builder.node_name(), "'");
  } else {
    if (!desc->colocation_constraints.empty()) {
      desc->node_builder.Attr(
          tensorflow::kColocationAttrName,

  return absl::OkStatus();
}

void SetMaximalSharding(NodeDefBuilder& node_builder) {
  xla::OpSharding sharding;
  sharding.set_type(xla::OpSharding::MAXIMAL);
  sharding.add_tile_assignment_dimensions(1);
  sharding.add_tile_assignment_devices(0);
  node_builder.Attr("_XlaSharding", sharding.SerializeAsString());
}

#include "tensorflow/core/framework/versions.pb.h"
#include "tensorflow/core/graph/algorithm.h"
#include "tensorflow/core/graph/graph.h"
#include "tensorflow/core/graph/graph_debug_info_builder.h"
#include "tensorflow/core/graph/node_builder.h"
#include "tensorflow/core/graph/tensor_id.h"
#include "tensorflow/core/grappler/utils/transitive_fanin.h"
#include "tensorflow/core/lib/core/errors.h"
#include "tensorflow/core/lib/strings/str_util.h"