code: def test_transform_standard(self):
      # check pandas standard transform works
  
      df = pd.DataFrame(
          {
              "A": ["A", "B", "A", "A", "A", "B", "B", "B"],
              "B": np.random.randn(8),
              "C": np.random.randn(8),
          }
      )
  
      mdf = pdml.ModelFrame(df)
      tm.assert_frame_equal(
          df.groupby("A").transform("mean"),
          mdf.groupby("A").transform("mean"),
      )
  
file_path: pandas-ml/pandas_ml/test/test_groupby.py
imports: import numpy
  import pandas
  import sklearn.datasets
  import pandas_ml
  import pandas_ml.util.testing
label_desc: Use image node_id 2 for calling the TestModelFrameGroupBy obj's underlying member method code with example usage: obj.test_transform_standard() without return types