class_docstr: Extension dtype for string data.
  
  .. warning::
  
     StringDtype is considered experimental. The implementation and
     parts of the API may change without warning.
  
  Parameters
  ----------
  storage : {"python", "pyarrow"}, optional
      If not given, the value of ``pd.options.mode.string_storage``.
  
  Attributes
  ----------
  None
  
  Methods
  -------
  None
  
  Examples
  --------
  >>> pd.StringDtype()
  string[python]
  
  >>> pd.StringDtype(storage="pyarrow")
  string[pyarrow]
code: def na_value(self) -> libmissing.NAType:
      return libmissing.NA
  
imports: from __future__ import annotations
  from typing import TYPE_CHECKING, Literal
  import numpy
  from pandas._config import get_option
  from pandas._libs import lib, missing
  from pandas._libs.arrays import NDArrayBacked
  from pandas._typing import AxisInt, Dtype, Scalar, npt, type_t
  from pandas.compat import pa_version_under7p0
  from pandas.compat.numpy import function
  from pandas.util._decorators import doc
  from pandas.core.dtypes.base import ExtensionDtype, StorageExtensionDtype, register_extension_dtype
  from pandas.core.dtypes.common import is_array_like, is_bool_dtype, is_dtype_equal, is_integer_dtype, is_object_dtype, is_string_dtype, pandas_dtype
  from pandas.core import ops
  from pandas.core.array_algos import masked_reductions
  from pandas.core.arrays import ExtensionArray, FloatingArray, IntegerArray
  from pandas.core.arrays.floating import FloatingDtype
  from pandas.core.arrays.integer import IntegerDtype
  from pandas.core.arrays.numpy_ import PandasArray
  from pandas.core.construction import extract_array
  from pandas.core.indexers import check_array_indexer
  from pandas.core.missing import isna
label_desc: Use image node_id 1 for calling the StringDtype obj's underlying member method code with example usage: obj.na_value() and returns: libmissing