return ret.value_;
  }
};

// Unpack a single argument case. Each argument is then cast.
template <class Fn, typename TReturn, class TSignatureArg,
          class... TSignatureRest>
class UneraseCallHelper<Fn, TReturn, TSignatureArg, TSignatureRest...> {
 public:
  template <typename... TArgsOut>
  static tensorflow::StatusOr<TaggedValue> Call(const char* name, Fn fn,