code: def _apply_search_backrefs(pattern, flags=0):
      
  
      if isinstance(pattern, (str, bytes)):
          re_verbose = bool(VERBOSE & flags)
          re_unicode = None
          if bool((ASCII | LOCALE) & flags):
              re_unicode = False
          elif bool(UNICODE & flags):
              re_unicode = True
          if not (flags & DEBUG):
              pattern = _cached_search_compile(pattern, re_verbose, re_unicode, type(pattern))
          else:  # pragma: no cover
              pattern = _bre_parse._SearchParser(pattern, re_verbose, re_unicode).parse()
      elif isinstance(pattern, Bre):
          if flags:
              raise ValueError("Cannot process flags argument with a compiled pattern")
          pattern = pattern._pattern
      elif isinstance(pattern, (_RE_TYPE, Bre)):
          if flags:
              raise ValueError("Cannot process flags argument with a compiled pattern!")
      else:
          raise TypeError("Not a string or compiled pattern!")
      return pattern
docs: Apply the search backrefs to the search pattern.