code: def test_block_transform_multiply(self, daskify, validation, factor):
      X = np.arange(100).reshape((25, 4))
      df = pd.DataFrame(X).rename(columns=str)
      if daskify:
          X = da.from_array(X, chunks=(5, 4))
          df = dd.from_pandas(df, npartitions=2)
      if factor:
          bt = BlockTransformer(
              multiply, validate=validation, factor=factor
          )
      else:
          bt = BlockTransformer(multiply, validate=validation)
      if daskify:
          assert dask.is_dask_collection(bt.transform(X))
          assert dask.is_dask_collection(bt.transform(df))
      if factor:
          da.utils.assert_eq(
              bt.transform(X), multiply(X, factor=factor)
          )
          dd.utils.assert_eq(
              bt.transform(df), multiply(df, factor=factor)
          )
      else:
          da.utils.assert_eq(bt.transform(X), multiply(X))
          dd.utils.assert_eq(bt.transform(df), multiply(df))
  
file_path: dask-ml/tests/preprocessing/test_block_transformer.py
imports: import dask
  import dask.array
  import dask.dataframe
  import numpy
  import pandas
  import pytest
  from dask_ml.preprocessing import BlockTransformer
  from dask_ml.utils import assert_estimator_equal
label_desc: Use image node_id 1 for calling the TestBlockTransformer obj's underlying member method code with example usage: obj.test_block_transform_multiply(daskify, validation, factor) without return types