docs: def init_config(config_file=None):
      """
      Initialize the configuration from a config file.
  
      The values in config_file will override those already loaded from the default
      configuration file (defaults.cfg, in current package).
  
      This method does not setup logging.
  
      @param config_file: The path to a configuration file.
      @type config_file: C{str}
  
      @raise ValueError: if the specified config_file could not be read.
      @see: L{init_logging}  
      """
      global config
  
      if config_file and os.path.exists(config_file):
          read = config.read([config_file])
          if not read:
              raise ValueError(
                  "Could not read configuration from file: %s" % config_file)