code: def _apply_search_backrefs(pattern, flags=0):
      
  
      if isinstance(pattern, (str, bytes)):
          re_verbose = VERBOSE & flags
          if flags & V0:
              re_version = V0
          elif flags & V1:
              re_version = V1
          else:
              re_version = 0
          if not (flags & DEBUG):
              pattern = _cached_search_compile(pattern, re_verbose, re_version, type(pattern))
          else:  # pragma: no cover
              pattern = _bregex_parse._SearchParser(pattern, re_verbose, re_version).parse()
      elif isinstance(pattern, Bregex):
          if flags:
              raise ValueError("Cannot process flags argument with a compiled pattern")
          pattern = pattern._pattern
      elif isinstance(pattern, _REGEX_TYPE):
          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.