code: def test_mask_inplace(self):
      # GH#8801
      df = DataFrame(np.random.default_rng(2).standard_normal((5, 3)))
      cond = df > 0
  
      rdf = df.copy()
  
      return_value = rdf.where(cond, inplace=True)
      assert return_value is None
      tm.assert_frame_equal(rdf, df.where(cond))
      tm.assert_frame_equal(rdf, df.mask(~cond))
  
      rdf = df.copy()
      return_value = rdf.where(cond, -df, inplace=True)
      assert return_value is None
      tm.assert_frame_equal(rdf, df.where(cond, -df))
      tm.assert_frame_equal(rdf, df.mask(~cond, -df))
  
file_path: pandas/pandas/tests/frame/indexing/test_mask.py
imports: import numpy
  from pandas import NA, DataFrame, Float64Dtype, Series, StringDtype, Timedelta, isna
  import pandas._testing
label_desc: Use image node_id 3 for calling the TestDataFrameMask obj's underlying member method code with example usage: obj.test_mask_inplace() without return types