docs: def load_config(config_file='~/.stancache.ini'):
      """ Load config file into default settings
      """
      if not os.path.exists(config_file):
          logging.warning('Config file does not exist: {}. Using default settings.'.format(config_file))
          return
      ## get user-level config in *.ini format
      config = configparser.ConfigParser()
      config.read(config_file)
      if not config.has_section('main'):
          raise ValueError('Config file {} has no section "main"'.format(config_file))
      for (key, val) in config.items('main'):
          _set_value(key.upper(), val)
      return