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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 remove_stale_css(portal):
 """Removes stale CSS """

    logger.info("Removing stale css ...")
    for css in CSS_TO_REMOVE:
        logger.info("Unregistering CSS %s" % css)
        portal.portal_css.unregisterResource(css)