code: def guess_chimera_path(search_all=False):
      paths = _search_chimera(CHIMERA_BINARY, CHIMERA_LOCATIONS, CHIMERA_PREFIX,
                              search_all=search_all)
      if not paths and search_all:
          headless = '{0[0]}{1}{0[1]}'.format(os.path.split(CHIMERA_BINARY), '-headless')
          paths = _search_chimera(headless, CHIMERA_LOCATIONS, CHIMERA_PREFIX,
                                  search_all=search_all)
      if not paths:
          sys.exit("Could not find UCSF Chimera.\n{}".format(_INSTRUCTIONS))
      return paths