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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def main(argv=None):
 """ben-doc entry point"""

    arguments = cli_common(__doc__, argv=argv)
    campaign_path = arguments['CAMPAIGN-DIR']
    driver = CampaignDriver(campaign_path, expandcampvars=False)
    with pushd(campaign_path):
        render(
            template=arguments['--template'],
            ostr=arguments['--output'],
            campaign=driver,
        )
    if argv is not None:
        return driver