code: def create_dummy_preprocessors():
      class DummyPreprocessorWithNothing(Preprocessor):
          _is_fittable = False
  
      class DummyPreprocessorWithPandas(DummyPreprocessorWithNothing):
          def _transform_pandas(
              self, df: "pd.DataFrame"
          ) -> "pd.DataFrame":
              return df
  
      class DummyPreprocessorWithNumpy(DummyPreprocessorWithNothing):
          batch_format = "numpy"
  
          def _transform_numpy(
              self, np_data: Union[np.ndarray, Dict[str, np.ndarray]]
          ) -> Union[np.ndarray, Dict[str, np.ndarray]]:
              return np_data
  
      class DummyPreprocessorWithPandasAndNumpy(
          DummyPreprocessorWithNothing
      ):
          def _transform_pandas(
              self, df: "pd.DataFrame"
          ) -> "pd.DataFrame":
              return df
  
          def _transform_numpy(
              self, np_data: Union[np.ndarray, Dict[str, np.ndarray]]
          ) -> Union[np.ndarray, Dict[str, np.ndarray]]:
              return np_data
  
      class DummyPreprocessorWithPandasAndNumpyPreferred(
          DummyPreprocessorWithNothing
      ):
          def _transform_pandas(
              self, df: "pd.DataFrame"
          ) -> "pd.DataFrame":
              return df
  
          def _transform_numpy(
              self, np_data: Union[np.ndarray, Dict[str, np.ndarray]]
          ) -> Union[np.ndarray, Dict[str, np.ndarray]]:
              return np_data
  
          def preferred_batch_format(cls) -> BatchFormat:
              return BatchFormat.NUMPY
  
      yield (
          DummyPreprocessorWithNothing(),
          DummyPreprocessorWithPandas(),
          DummyPreprocessorWithNumpy(),
          DummyPreprocessorWithPandasAndNumpy(),
          DummyPreprocessorWithPandasAndNumpyPreferred(),
      )
  
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 1 for calling a global function with example usage: create_dummy_preprocessors() and returns: df, np_data, df, np_data, df, np_data, BatchFormat