return absl::OkStatus();
        case 16:
          *tf_dtype = TF_DataType::TF_INT16;
          return absl::OkStatus();
        case 32:
          *tf_dtype = TF_DataType::TF_INT32;
          return absl::OkStatus();
        case 64:
          *tf_dtype = TF_DataType::TF_INT64;
          return absl::OkStatus();
        default:
          return tensorflow::errors::InvalidArgument("Unsupported Int bits: ",

    // Calculate Grad
    std::string name = "relu_grad";
    TF_RETURN_IF_ERROR(ReluGrad(ctx, upstream_grad, activations,
                                &grad_inputs[0], name.c_str()));
    return absl::OkStatus();
  }
  ~ReluGradientFunction() override {
    for (auto output : forward_outputs_) {
      if (output) {
        output->Unref();
      }
    }
  }

 private:

    return absl::OkStatus();
  }
  Status SetAttrFloat(const char* attr_name, float value) override {
    op_->node_builder.Attr(attr_name, value);
    return absl::OkStatus();
  }
  Status SetAttrBool(const char* attr_name, bool value) override {
    op_->node_builder.Attr(attr_name, value);
    return absl::OkStatus();
  }

        "Trying to register filesystem without `cleanup` operation");

  return OkStatus();
}

// Validates the random access file operations supplied by the plugin.
static Status ValidateHelper(const TF_RandomAccessFileOps* ops) {
  if (ops == nullptr) {
    // We allow filesystems where files can only be written to (from TF code)
    return OkStatus();
  }

  if (ops->cleanup == nullptr)

  return IsRefType(dt)
             ? InvalidArgument("Output ", idx, " of node '", node->name(),
                               "' has a reference type ", DataTypeString(dt))
             : absl::OkStatus();
}

// Converts `ninputs` and `inputs` into `inputs_tensors` and `input_nodes` and
// does various checks while doing so. `input_nodes` will contain the same

  forward_op_->inputs.push_back(input);
  return absl::OkStatus();
}
Status AddInputList(AbstractOperation* op_,
                    absl::Span<AbstractTensorHandle* const> inputs,
                    ForwardOperation* forward_op_) {
  TF_RETURN_IF_ERROR(op_->AddInputList(inputs));
  for (auto input : inputs) {
    forward_op_->inputs.push_back(input);
  }
  return absl::OkStatus();
}

    CHECK_EQ(grad_outputs.size(), 1);
    CHECK_EQ(grad_inputs.size(), 1);
    grad_inputs[0] = grad_outputs[0];
    if (grad_inputs[0]) {
      grad_inputs[0]->Ref();
    }
    return absl::OkStatus();
  }
};

// Computes:
//
// @tf.custom_gradient
// def f(input):
//   def grad(grads):
//     return grads[0]
//   return tf.exp(input), grad
// outputs = [f(inputs[0])]

    DCHECK(grad_outputs[0]);
    grad_inputs[0] = grad_outputs[0];
    grad_inputs[1] = grad_outputs[0];

    grad_inputs[0]->Ref();
    grad_inputs[1]->Ref();
    return absl::OkStatus();
  }
  ~AddGradientFunction() override {}
};

class ExpGradientFunction : public GradientFunction {
 public:
  explicit ExpGradientFunction(AbstractTensorHandle* exp) : exp_(exp) {
    exp->Ref();
  }

  VALIDATE_MEMBER(TP_OptimizerRegistrationParams, params, device_type);
  return absl::OkStatus();
}

absl::Status ValidateTPOptimizer(const TP_Optimizer& optimizer) {
  VALIDATE_STRUCT_SIZE(TP_Optimizer, optimizer, TP_OPTIMIZER_STRUCT_SIZE);
  VALIDATE_MEMBER(TP_Optimizer, optimizer, optimize_func);
  return absl::OkStatus();
}

absl::Status ValidateTPOptimizerConfigs(const TP_OptimizerConfigs& configs) {

  TF_DeleteTensor(model_out_tensor);

  // If the output is a scalar, then return the scalar output
  if (num_dims_out == 0) {
    outputs[0] = model_out.release();
    return absl::OkStatus();
  }

  // Else, reduce sum the output to get a scalar

  // Will sum all dimensions, so get a Tensor containing [0,...,num_dims_out-1].
  AbstractTensorHandlePtr sum_dims;
  {