code: def test_custom_model(self):
      ray.init(object_store_memory=1000 * 1024 * 1024)
      ModelCatalog.register_custom_model("foo", CustomModel)
      p1 = ModelCatalog.get_model_v2(
          obs_space=Box(0, 1, shape=(3,), dtype=np.float32),
          action_space=Discrete(5),
          num_outputs=5,
          model_config={"custom_model": "foo"},
      )
      self.assertEqual(str(type(p1)), str(CustomModel))
  
imports: from functools import partial
  from gymnasium.spaces import Box, Dict, Discrete, Tuple
  import numpy
  import unittest
  import ray
  from ray.rllib.models import ActionDistribution, ModelCatalog, MODEL_DEFAULTS
  from ray.rllib.models.preprocessors import Preprocessor, TupleFlatteningPreprocessor
  from ray.rllib.models.tf.tf_action_dist import MultiActionDistribution, TFActionDistribution
  from ray.rllib.models.tf.tf_modelv2 import TFModelV2
  from ray.rllib.utils.annotations import override
  from ray.rllib.utils.framework import try_import_tf, try_import_torch
  from ray.rllib.utils.spaces.space_utils import get_dummy_batch_for_space
  from ray.rllib.utils.torch_utils import convert_to_torch_tensor
label_desc: Use image node_id 3 for calling the TestModelCatalog obj's underlying member method code with example usage: obj.test_custom_model() without return types