code: def test_read_from_file(self, convert_to_coding_scheme):
      conll_reader = Conll2003DatasetReader(
          convert_to_coding_scheme=convert_to_coding_scheme
      )
      instances = ensure_list(
          conll_reader.read(
              AllenNlpTestCase.FIXTURES_ROOT / "data" / "conll2003.txt"
          )
      )
  
      if convert_to_coding_scheme is None:
          expected_labels = [
              "I-ORG",
              "O",
              "I-PER",
              "O",
              "O",
              "I-LOC",
              "O",
          ]
      else:
          expected_labels = [
              "U-ORG",
              "O",
              "U-PER",
              "O",
              "O",
              "U-LOC",
              "O",
          ]
  
      fields = instances[0].fields
      tokens = [t.text for t in fields["tokens"].tokens]
      assert tokens == [
          "U.N.",
          "official",
          "Ekeus",
          "heads",
          "for",
          "Baghdad",
          ".",
      ]
      assert fields["tags"].labels == expected_labels
  
      fields = instances[1].fields
      tokens = [t.text for t in fields["tokens"].tokens]
      assert tokens == [
          "AI2",
          "engineer",
          "Joel",
          "lives",
          "in",
          "Seattle",
          ".",
      ]
      assert fields["tags"].labels == expected_labels
  
file_path: allennlp/tests/data/dataset_readers/conll2003_test.py
imports: import pytest
  from allennlp.data.dataset_readers.conll2003 import Conll2003DatasetReader
  from allennlp.common.checks import ConfigurationError
  from allennlp.common.util import ensure_list
  from allennlp.common.testing import AllenNlpTestCase
label_desc: Use image node_id 2 for calling the TestConll2003Reader obj's underlying member method code with example usage: obj.test_read_from_file(convert_to_coding_scheme) without return types