code: def test_dataframe_dummies_drop_first(self, df, sparse):
      df = df[["A", "B"]]
      result = get_dummies(df, drop_first=True, sparse=sparse)
      expected = DataFrame(
          {"A_b": [0, 1, 0], "B_c": [0, 0, 1]}, dtype=bool
      )
      if sparse:
          expected = expected.apply(SparseArray, fill_value=False)
      tm.assert_frame_equal(result, expected)
  
imports: import re
  import unicodedata
  import numpy
  import pytest
  import pandas.util._test_decorators
  from pandas.core.dtypes.common import is_integer_dtype
  import pandas
  from pandas import ArrowDtype, Categorical, CategoricalDtype, CategoricalIndex, DataFrame, Index, RangeIndex, Series, SparseDtype, get_dummies
  import pandas._testing
  from pandas.core.arrays.sparse import SparseArray
label_desc: Use image node_id 27 for calling the TestGetDummies obj's underlying member method code with example usage: obj.test_dataframe_dummies_drop_first(df, sparse) without return types