code: def _remove_whitespace(s, regex=_RE_WHITESPACE):
      """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 : regex
          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 distutils.version import LooseVersion
  import numbers
  import os
  import re
  import pandas.compat
  from pandas.compat import binary_type, iteritems, lmap, lrange, raise_with_traceback, string_types, u
  from pandas.errors import AbstractMethodError, EmptyDataError
  from pandas.core.dtypes.common import is_list_like
  from pandas import Series
  from pandas.io.common import _is_url, _validate_header_arg, urlopen
  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