code: def _remove_whitespace(
      s: str, regex: Pattern = _RE_WHITESPACE
  ) -> str:
      """
      Replace extra whitespace inside of a string with a single space.
  
      Parameters
      ----------
      s : str or unicode
          The string from which to remove extra whitespace.
      regex : re.Pattern
          The regular expression to use to remove extra whitespace.
  
      Returns
      -------
      subd : str or unicode
          `s` with all extra whitespace replaced with a single space.
      """
      return regex.sub(" ", s.strip())
  
imports: from __future__ import annotations
  from collections import abc
  import numbers
  import re
  from typing import TYPE_CHECKING, Iterable, Literal, Pattern, Sequence, cast
  from pandas._libs import lib
  from pandas._typing import BaseBuffer, DtypeBackend, FilePath, ReadBuffer
  from pandas.compat._optional import import_optional_dependency
  from pandas.errors import AbstractMethodError, EmptyDataError
  from pandas.util._validators import check_dtype_backend
  from pandas.core.dtypes.common import is_list_like
  from pandas import isna
  from pandas.core.indexes.base import Index
  from pandas.core.indexes.multi import MultiIndex
  from pandas.core.series import Series
  from pandas.io.common import file_exists, get_handle, is_url, stringify_path, urlopen, validate_header_arg
  from pandas.io.formats.printing import pprint_thing
  from pandas.io.parsers import TextParser
label_desc: Use image node_id 2 for calling a global function with example usage: _remove_whitespace(s, regex) and returns: regex