code: def test_validate_none():
      service_settings = LibrarySettings()
  
      class SomeValidatedModel(Model):
          def _predict(self, item):
              return item
  
      m = SomeValidatedModel(service_settings=service_settings)
      assert m({"x": 10}) == {"x": 10}
      assert m(1) == 1
  
file_path: modelkit/tests/test_validate.py
imports: from typing import Any, Dict, List
  import pydantic
  import pytest
  from modelkit.core.errors import ItemValidationException, ModelkitDataValidationException, ReturnValueValidationException
  from modelkit.core.model import AsyncModel, Model
  from modelkit.core.settings import LibrarySettings
label_desc: Use image node_id 6 for calling a global function with example usage: test_validate_none() and returns: item