code: def test_autoscaling_policy_serializations(policy):
      """Test that autoscaling policy can be serialized and deserialized.
  
      This test checks that the autoscaling policy can be serialized and deserialized for
      when the policy is a function, a string, or None (default).
      """
      autoscaling_config = AutoscalingConfig()
      if policy:
          autoscaling_config = AutoscalingConfig(policy=policy)
  
      config = DeploymentConfig.from_default(
          autoscaling_config=autoscaling_config
      )
      deserialized_autoscaling_policy = (
          DeploymentConfig.from_proto_bytes(
              config.to_proto_bytes()
          ).autoscaling_config.get_policy()
      )
  
      if policy is None:
          assert (
              deserialized_autoscaling_policy
              == default_autoscaling_policy
          )
      else:
          assert (
              deserialized_autoscaling_policy()
              == fake_policy_return_value
          )
  
imports: import pytest
  from ray import cloudpickle
  from ray._private.pydantic_compat import ValidationError
  from ray._private.utils import import_attr
  from ray.serve._private.config import DeploymentConfig, ReplicaConfig, _proto_to_dict
  from ray.serve._private.constants import DEFAULT_AUTOSCALING_POLICY, DEFAULT_GRPC_PORT
  from ray.serve._private.utils import DEFAULT
  from ray.serve.autoscaling_policy import default_autoscaling_policy
  from ray.serve.config import AutoscalingConfig, DeploymentMode, HTTPOptions, ProxyLocation, gRPCOptions
  from ray.serve.generated.serve_pb2 import AutoscalingConfig
  from ray.serve.generated.serve_pb2 import DeploymentConfig
  from ray.serve.generated.serve_pb2 import DeploymentLanguage
  from ray.serve.generated.serve_pb2_grpc import add_UserDefinedServiceServicer_to_server
  from ray.serve.schema import DeploymentSchema, HTTPOptionsSchema, ServeApplicationSchema, ServeDeploySchema
label_desc: Use image node_id 10 for calling a global function with example usage: test_autoscaling_policy_serializations(policy) without return types