code: def test_index_missing(any_string_dtype, method, exp):
      ser = Series(
          ["abcb", "ab", "bcbe", np.nan], dtype=any_string_dtype
      )
      expected_dtype = (
          np.float64
          if any_string_dtype in object_pyarrow_numpy
          else "Int64"
      )
  
      result = getattr(ser.str, method)("b")
      expected = Series(exp + [np.nan], dtype=expected_dtype)
      tm.assert_series_equal(result, expected)
  
imports: from datetime import datetime, timedelta
  import numpy
  import pytest
  from pandas import DataFrame, Index, MultiIndex, Series
  import pandas._testing
  from pandas.core.strings.accessor import StringMethods
  from pandas.tests.strings import object_pyarrow_numpy
label_desc: Use image node_id 19 for calling a global function with example usage: test_index_missing(any_string_dtype, method, exp) without return types