code: def test_validate(self, mocker, daskify, validate):
      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)
      m = mocker.patch(
          "dask_ml.preprocessing._block_transformer.check_array"
      )
      bt = BlockTransformer(lambda x: x, validate=validate)
      if validate:
          _ = bt.transform(X)
          m.assert_called_once()
          m.reset_mock()
          _ = bt.transform(df)
          m.assert_called_once()
      else:
          _ = bt.transform(X)
          m.assert_not_called()
          _ = bt.transform(df)
          m.assert_not_called()
  
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 2 for calling the TestBlockTransformer obj's underlying member method code with example usage: obj.test_validate(mocker, daskify, validate) without return types