def METHOD_NAME(filename, abspath=True):
    """set_file FILENAME
       Sets the default configuration file, used by mySociety::Config::get.
       By default this will store an absolute path to the file so things
       still work after a change of current working directory. If you really
       want this to be a relative path set the optional argument abspath to
       something false.
    """
    global main_config_filename
    main_config_filename = os.path.abspath(filename) if abspath else filename