code: def test_find_fields(
      self,
      model: lit_model.Model,
      to_find: lit_types.LitType,
      expected_fields: list[str],
      align_field: Optional[str],
  ):
      found = self.hotflip.find_fields(
          model.output_spec(), to_find, align_field
      )
      self.assertEqual(found, expected_fields)
  
imports: from typing import Optional
  from absl.testing import absltest
  from absl.testing import parameterized
  from lit_nlp.api import dataset
  from lit_nlp.api import model
  from lit_nlp.api import types
  from lit_nlp.components import hotflip
  from lit_nlp.lib import utils
  import numpy
label_desc: Use image node_id 3 for calling the HotflipTest obj's underlying member method code with example usage: obj.test_find_fields(model, to_find, expected_fields, align_field) without return types