code: def multiply(x, factor=4):
      return factor * x
  
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 a global function with example usage: multiply(x, factor) and returns: unknown