code: def test_replace_regex_dtype_series(self, regex):
      # GH-48644
      series = pd.Series(["0"])
      expected = pd.Series([1])
      msg = "Downcasting behavior in `replace`"
      with tm.assert_produces_warning(FutureWarning, match=msg):
          result = series.replace(to_replace="0", value=1, regex=regex)
      tm.assert_series_equal(result, expected)
  
imports: import re
  import numpy
  import pytest
  from pandas._config import using_pyarrow_string_dtype
  import pandas
  import pandas._testing
  from pandas.core.arrays import IntervalArray
label_desc: Use image node_id 47 for calling the TestSeriesReplace obj's underlying member method code with example usage: obj.test_replace_regex_dtype_series(regex) without return types