code: def test_transform_unlabelled():
      ul_dataset = load_unlabelled_data()
      # transforming y should raise an exception
      with pytest.raises(ValueError):
          dc.trans.transformers.Transformer(transform_y=True).transform(
              ul_dataset
          )
  
      # transforming w should raise an exception
      with pytest.raises(ValueError):
          dc.trans.transformers.Transformer(transform_w=True).transform(
              ul_dataset
          )
  
      # transforming X should be okay
      dc.trans.NormalizationTransformer(
          transform_X=True, dataset=ul_dataset
      ).transform(ul_dataset)
  
file_path: deepchem/deepchem/trans/tests/test_normalization.py
imports: import os
  import deepchem
  import numpy
  import pytest
label_desc: Use image node_id 3 for calling a global function with example usage: test_transform_unlabelled() without return types