docs: def cache_master(self, saltenv='base', cachedir=None):
          '''
          Download and cache all files on a master in a specified environment
          '''
          ret = []
          for path in self.file_list(saltenv):
              ret.append(
                  self.cache_file(
                      salt.utils.url.create(path), saltenv, cachedir=cachedir)
              )
          return ret