code: def test_replace_mixed_types_with_string(self):
      # Testing mixed
      s = pd.Series([1, 2, 3, "4", 4, 5])
      msg = "Downcasting behavior in `replace`"
      with tm.assert_produces_warning(FutureWarning, match=msg):
          result = s.replace([2, "4"], np.nan)
      expected = pd.Series([1, np.nan, 3, np.nan, 4, 5])
      tm.assert_series_equal(expected, result)
  
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 24 for calling the TestSeriesReplace obj's underlying member method code with example usage: obj.test_replace_mixed_types_with_string() without return types