code: def test_round_nonunique_categorical(self):
      # See GH#21809
      idx = pd.CategoricalIndex(["low"] * 3 + ["hi"] * 3)
      df = DataFrame(
          np.random.default_rng(2).random((6, 3)), columns=list("abc")
      )
  
      expected = df.round(3)
      expected.index = idx
  
      df_categorical = df.copy().set_index(idx)
      assert df_categorical.shape == (6, 3)
      result = df_categorical.round(3)
      assert result.shape == (6, 3)
  
      tm.assert_frame_equal(result, expected)
  
file_path: pandas/pandas/tests/frame/methods/test_round.py
imports: import numpy
  import pytest
  import pandas
  from pandas import DataFrame, Series, date_range
  import pandas._testing
label_desc: Use image node_id 7 for calling the TestDataFrameRound obj's underlying member method code with example usage: obj.test_round_nonunique_categorical() without return types