code: def test_repr(preprocessor):
      representation = repr(preprocessor)
  
      assert len(representation) < MAX_REPR_LENGTH
      pattern = re.compile(
          f"^{preprocessor.__class__.__name__}\\((.*)\\)$"
      )
      assert pattern.match(representation)
  
imports: import re
  import warnings
  from typing import Dict, Union
  from unittest.mock import patch
  import numpy
  import pandas
  import pyarrow
  import pytest
  import ray
  from ray.air.constants import MAX_REPR_LENGTH
  from ray.air.util.data_batch_conversion import BatchFormat
  from ray.data.preprocessor import Preprocessor
  from ray.data.preprocessors import BatchMapper, Categorizer, Chain, Concatenator, CountVectorizer, FeatureHasher, HashingVectorizer, LabelEncoder, MaxAbsScaler, MinMaxScaler, MultiHotEncoder, Normalizer, OneHotEncoder, OrdinalEncoder, PowerTransformer, RobustScaler, SimpleImputer, StandardScaler, Tokenizer
label_desc: Use image node_id 2 for calling a global function with example usage: test_repr(preprocessor) without return types