code: def test_replace_unicode(any_string_dtype):
      ser = Series(
          [b"abcd,\xc3\xa0".decode("utf-8")], dtype=any_string_dtype
      )
      expected = Series(
          [b"abcd, \xc3\xa0".decode("utf-8")], dtype=any_string_dtype
      )
      with tm.maybe_produces_warning(
          PerformanceWarning, using_pyarrow(any_string_dtype)
      ):
          result = ser.str.replace(
              r"(?<=\w),(?=\w)", ", ", flags=re.UNICODE, regex=True
          )
      tm.assert_series_equal(result, expected)
  
imports: from datetime import datetime
  import re
  import numpy
  import pytest
  from pandas.errors import PerformanceWarning
  import pandas.util._test_decorators
  import pandas
  from pandas import Series, _testing
  from pandas.tests.strings import _convert_na_value, object_pyarrow_numpy
label_desc: Use image node_id 15 for calling a global function with example usage: test_replace_unicode(any_string_dtype) without return types