code: def test_drop_first(self, daskify):
      if daskify:
          df = dd.from_pandas(dummy, 2)
      else:
          df = dummy
      de = dpp.DummyEncoder(drop_first=True)
      trn = de.fit_transform(df)
      assert len(trn.columns) == 8
  
      result = de.inverse_transform(trn)
      if daskify:
          result, df = compute(result, df)
      tm.assert_frame_equal(result, dummy)
  
imports: from copy import copy
  import dask
  import dask.array
  import dask.dataframe
  import numpy
  import pandas
  import pandas.testing
  import pytest
  import sklearn.preprocessing
  from dask import compute
  from dask.array.utils import assert_eq
  from dask.dataframe.utils import assert_eq
  from pandas.api.types import is_categorical_dtype, is_object_dtype
  from sklearn.exceptions import NotFittedError
  import dask_ml.preprocessing
  from dask_ml.datasets import make_classification
  from dask_ml.utils import assert_estimator_equal
label_desc: Use image node_id 3 for calling the TestDummyEncoder obj's underlying member method code with example usage: obj.test_drop_first(daskify) without return types