// Our SavedModel import requires input_signature on the tf.function, so
      // we never need to handle the kwonlyargs.
      auto positional_arg_structure =
          concrete_function.canonicalized_input_signature()
              .tuple_value()
              .values(0);
      StructuredValueLinearizer input_linearizer(positional_arg_structure,
                                                 builder.getContext());