ASSERT_EQ(func_, nullptr);
      return;
    }

    ASSERT_EQ(TF_OK, TF_GetCode(s_)) << TF_Message(s_);
    ASSERT_NE(func_, nullptr);
    ASSERT_EQ(std::string(func_name_), std::string(TF_FunctionName(func_)));
    TF_GraphCopyFunction(host_graph_, func_, nullptr, s_);
    ASSERT_EQ(TF_OK, TF_GetCode(s_)) << TF_Message(s_);
  }

  TF_Operation* Use(const std::vector<TF_Operation*>& inputs) {

// Returns the name of the graph function.
// The return value points to memory that is only usable until the next
// mutation to *func.
TF_CAPI_EXPORT extern const char* TF_FunctionName(TF_Function* func);

// Write out a serialized representation of `func` (as a FunctionDef protocol
// message) to `output_func_def` (allocated by TF_NewBuffer()).