code: def test_make_modified_input_new_field(self):
      ex = {
          "foo": 123,
          "bar": 234,
          "_id": "a1b2c3",
          "_meta": {"parentId": "000000"},
      }
      new_ex = utils.make_modified_input(
          ex, {"baz": "spam and eggs"}, "testFn"
      )
      expected = {
          "foo": 123,
          "bar": 234,
          "baz": "spam and eggs",
          "_id": "",
          "_meta": {
              "parentId": "a1b2c3",
              "added": True,
              "source": "testFn",
          },
      }
      self.assertEqual(new_ex, expected)
  
imports: from collections.abc import Callable, Sequence
  import copy
  from typing import Any, Optional, TypeVar, Union
  from absl.testing import absltest
  from absl.testing import parameterized
  from lit_nlp.api import types
  from lit_nlp.lib import utils
  import numpy
label_desc: Use image node_id 19 for calling the UtilsTest obj's underlying member method code with example usage: obj.test_make_modified_input_new_field() without return types