docs: def find_config_file(self, project=None, extension='.conf'):
          """Return the config file.
  
          :param project: "zvmsdk"
          :param extension: the type of the config file
  
          """
          cfg_dirs = self._get_config_dirs()
          config_files = self._search_dirs(cfg_dirs, project, extension)
  
          return config_files