def METHOD_NAME(self, filename):
    job = Job.load(filename)
    # init config
    if 'PYWPS_CFG' in os.environ:
        config.load_configuration(os.environ['PYWPS_CFG'])
    # update PATH
    os.environ['PATH'] = "{0}:{1}".format(
        config.get_config_value('processing', 'path'),
        os.environ.get('PATH'))
    # cd into workdir
    os.chdir(job.workdir)
    # init logger ... code copied from app.Service
    if config.get_config_value('logging', 'file') and config.get_config_value('logging', 'level'):
        LOGGER.setLevel(getattr(logging, config.get_config_value('logging', 'level')))
        if not LOGGER.handlers:  # hasHandlers in Python 3.x
            fh = logging.FileHandler(config.get_config_value('logging', 'file'))
            fh.setFormatter(logging.Formatter(config.get_config_value('logging', 'format')))
            LOGGER.addHandler(fh)
    else:  # NullHandler
        if not LOGGER.handlers:
            LOGGER.addHandler(logging.NullHandler())
    job.run()