code: def test_pandas_replace_na(self):
      # GH#43344
      ser = pd.Series(
          ["AA", "BB", "CC", "DD", "EE", "", pd.NA], dtype="string"
      )
      regex_mapping = {
          "AA": "CC",
          "BB": "CC",
          "EE": "CC",
          "CC": "CC-REPL",
      }
      result = ser.replace(regex_mapping, regex=True)
      exp = pd.Series(
          ["CC", "CC", "CC-REPL", "DD", "CC", "", pd.NA], dtype="string"
      )
      tm.assert_series_equal(result, exp)
  
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 41 for calling the TestSeriesReplace obj's underlying member method code with example usage: obj.test_pandas_replace_na() without return types