Perform backup action on set driver

    :param file: Name of the file to be used by the driver
    :param host: Corresponding host name associated with file

def backup_file(*, file, host):
    """
    Perform backup action on set driver

    :param file: Name of the file to be used by the driver
    :param host: Corresponding host name associated with file
    """
    if _driver:
        log.msg_debug("[{driver}] Backing up file '{file}'"
                      .format(driver=_driver.get_name(), file=file))
        _driver.backup_file(file=file, host=host)