code: def test_mean_functions_composite_type(
      mean_function_1: MeanFunction,
      mean_function_2: MeanFunction,
      operation: str,
  ) -> None:
      if operation == "+":
          mean_composed = mean_function_1 + mean_function_2
          assert isinstance(mean_composed, Additive)
      elif operation == "*":
          mean_composed = mean_function_1 * mean_function_2
          assert isinstance(mean_composed, Product)
      else:
          raise NotImplementedError
  
imports: from typing import Any, Sequence, Tuple, Type
  import numpy
  import pytest
  import tensorflow_probability
  from check_shapes import check_shapes
  from numpy.testing import assert_allclose
  import gpflow
  from gpflow.base import AnyNDArray, TensorType
  from gpflow.config import default_int
  from gpflow.functions import Additive, Constant, Linear, MeanFunction, Polynomial, Product, SwitchedMeanFunction, Zero
  from gpflow.inducing_variables import InducingPoints
label_desc: Use image node_id 2 for calling a global function with example usage: test_mean_functions_composite_type(mean_function_1, mean_function_2, operation) without return types