code: def test_min_max(method, skipna, dtype):
      arr = pd.Series(["a", "b", "c", None], dtype=dtype)
      result = getattr(arr, method)(skipna=skipna)
      if skipna:
          expected = "a" if method == "min" else "c"
          assert result == expected
      else:
          assert result is na_val(arr.dtype)
  
imports: import operator
  import numpy
  import pytest
  from pandas.compat.pyarrow import pa_version_under12p0
  from pandas.core.dtypes.common import is_dtype_equal
  import pandas
  import pandas._testing
  from pandas.core.arrays.string_arrow import ArrowStringArray, ArrowStringArrayNumpySemantics
label_desc: Use image node_id 28 for calling a global function with example usage: test_min_max(method, skipna, dtype) without return types