code: def test_leaf_components_only_returns_parameters_and_variables(
      module: Any,
  ) -> None:
      for path, variable in leaf_components(module).items():
          assert isinstance(variable, tf.Variable) or isinstance(
              variable, gpflow.Parameter
          )
  
imports: from typing import Any, Callable, Mapping, Optional, Type
  import numpy
  import pytest
  import tensorflow
  from _pytest.fixtures import SubRequest
  from packaging.version import Version
  import gpflow
  from gpflow.base import AnyNDArray
  from gpflow.config import Config, as_context
  from gpflow.utilities import set_trainable
  from gpflow.utilities.traversal import _merge_leaf_components, leaf_components, tabulate_module_summary
label_desc: Use image node_id 6 for calling a global function with example usage: test_leaf_components_only_returns_parameters_and_variables(module) without return types