code: def _replace_fun_unescape(m):
      
      slsh = b'\\'.decode('ascii')
      s = m.group(0)
      count = s.count(slsh)
      if count % 2 == 0:
          return s
      else:
          if sys.hexversion >= 0x03000000:
              c = chr(int(s[(count + 1):], base=16))
          else:
              c = unichr(int(s[(count + 1):], base=16))
          return slsh * (count - 1) + c
docs: Decode single hex/unicode escapes found in regex matches.
  
      Supports single hex/unicode escapes of the form ``'\\xYY'``,
      ``'\\uYYYY'``, and ``'\\UYYYYYYYY'`` where Y is a hex digit. Only
      decodes if there is an odd number of backslashes.
  
      .. versionadded:: 0.2
  
      Parameters
      ----------
      m : regex match
  
      Returns
      -------
      c : str
          The unescaped character.