code: def test_to_file(self):
      # Test to_file works with or without preference orders
      params_dict = {"keyA": "valA", "keyB": "valB"}
      expected_ordered_params_dict = OrderedDict(
          {"keyB": "valB", "keyA": "valA"}
      )
      params = Params(params_dict)
      file_path = self.TEST_DIR / "config.jsonnet"
      # check with preference orders
      params.to_file(file_path, [["keyB", "keyA"]])
      with open(file_path, "r") as handle:
          ordered_params_dict = OrderedDict(json.load(handle))
      assert json.dumps(expected_ordered_params_dict) == json.dumps(
          ordered_params_dict
      )
      # check without preference orders doesn't give error
      params.to_file(file_path)
  
imports: import json
  import os
  import re
  from collections import OrderedDict
  import pytest
  from allennlp.common.checks import ConfigurationError
  from allennlp.common.params import infer_and_cast, Params, remove_keys_from_params, with_overrides
  from allennlp.common.testing import AllenNlpTestCase
label_desc: Use image node_id 13 for calling the TestParams obj's underlying member method code with example usage: obj.test_to_file() without return types