namespace tensorflow {
using tensorflow::IdentityShapeRepresentationFn;

class XlaCpuDeviceFactory : public DeviceFactory {
 public:
  Status ListPhysicalDevices(std::vector<string>* devices) override;
  Status CreateDevices(const SessionOptions& options, const string& name_prefix,
                       std::vector<std::unique_ptr<Device>>* devices) override;
};

Status XlaCpuDeviceFactory::ListPhysicalDevices(std::vector<string>* devices) {

#include "tensorflow/core/lib/core/status.h"

namespace tensorflow {

class XlaGpuDeviceFactory : public DeviceFactory {
 public:
  Status ListPhysicalDevices(std::vector<string>* devices) override;
  Status CreateDevices(const SessionOptions& options, const string& name_prefix,
                       std::vector<std::unique_ptr<Device>>* devices) override;
};

Status XlaGpuDeviceFactory::ListPhysicalDevices(std::vector<string>* devices) {

  if (!status.ok()) {
    done(status);
  }
}

class TpuNodeDeviceFactory : public DeviceFactory {
 public:
  Status ListPhysicalDevices(std::vector<string>* devices) override;
  Status CreateDevices(const SessionOptions& options, const string& name_prefix,
                       std::vector<std::unique_ptr<Device>>* devices) override;
};

Status TpuNodeDeviceFactory::ListPhysicalDevices(std::vector<string>* devices) {

    auto device_factory = DeviceFactory::GetFactory(device_type);
    SessionOptions options;
    std::vector<std::unique_ptr<Device>> devices;
    Status s = device_factory->CreateDevices(
        options, "/job:worker/replica:0/task:0", &devices);
    device_ = std::move(devices[0]);

    tensorflow::AllocatorAttributes host_alloc_attr;
    host_alloc_attr.set_on_host(true);

  void SetDevice(const string& device_type) {
    auto device_factory = DeviceFactory::GetFactory(device_type);
    SessionOptions options;
    std::vector<std::unique_ptr<Device>> devices;
    Status s = device_factory->CreateDevices(
        options, "/job:worker/replica:0/task:0", &devices);
    device_ = std::move(devices[0]);

    AllocatorAttributes host_alloc_attr;
    host_alloc_attr.set_on_host(true);

  if (!cpu_factory) {
    return errors::NotFound(
        "CPU Factory not registered. Can't run EncapsulateSubgraphsPass");
  }
  TF_RETURN_IF_ERROR(cpu_factory->CreateDevices(
      session_options, "/job:localhost/replica:0/task:0", &devices));
  if (devices.empty()) {
    return errors::NotFound(
        "Failed to create a CPU device for EncapsulateSubgraphsPass");
  }

    `state_is_tuple=True`. For a quick fix while transitioning to the new
    default, simply pass the argument `state_is_tuple=False`.
*   DeviceFactory's AddDevices and CreateDevices functions now return a Status
    instead of void.
*   Int32 elements of list(type) arguments are no longer placed in host memory
    by default. If necessary, a list(type) argument to a kernel can be placed in