code: def test_append(self, ci):
      # append cats with the same categories
      result = ci[:3].append(ci[3:])
      tm.assert_index_equal(result, ci, exact=True)
  
      foos = [ci[:1], ci[1:3], ci[3:]]
      result = foos[0].append(foos[1:])
      tm.assert_index_equal(result, ci, exact=True)
  
file_path: pandas/pandas/tests/indexes/categorical/test_append.py
imports: import pytest
  from pandas import CategoricalIndex, Index
  import pandas._testing
label_desc: Use image node_id 2 for calling the TestAppend obj's underlying member method code with example usage: obj.test_append(ci) without return types