TFE_OpAddInput(op, h, status);
    ASSERT_TRUE(TF_GetCode(status) == TF_OK) << TF_Message(status);

    std::vector<TFE_TensorHandle*> result;
    result.push_back(nullptr);
    int num_retvals = 1;
    TFE_Execute(op, result.data(), &num_retvals, status);
    TFE_DeleteOp(op);
    ASSERT_TRUE(TF_GetCode(status) == TF_OK) << TF_Message(status);
    ASSERT_EQ(num_retvals, 1);

          absl::Span<tensorflow::ImmediateExecutionTensorHandle*>(
              tensorflow::unwrap(handles), *num_handles),
          &result);
      return tensorflow::wrap(result);
    }
    tensor_handles.push_back(
        tensorflow::TensorHandleFromInterface(unwrapped_handle));
  }
  tensorflow::EagerContext* context =
      tensorflow::ContextFromInterface(tensorflow::unwrap(ctx));
  tensorflow::TensorHandle* handle = nullptr;

const char* kNegStackToString = "File \"neg.cc\", line 15, in beta";

std::vector<IOSpec> M(const std::initializer_list<string>& names) {
  std::vector<IOSpec> v;
  for (const string& name : names) {
    v.push_back(IOSpec(name, DT_INVALID));
  }
  return v;
}

// Specification for an expected edge.
// src is either:
// - input name (as it appears in FunctionDef)
// - name of output tensor (in nested "add:z:0" format)

pkg container/list, method (*List) Len() int
pkg container/list, method (*List) MoveToBack(*Element)
pkg container/list, method (*List) MoveToFront(*Element)
pkg container/list, method (*List) PushBack(interface{}) *Element
pkg container/list, method (*List) PushBackList(*List)
pkg container/list, method (*List) PushFront(interface{}) *Element
pkg container/list, method (*List) PushFrontList(*List)