def METHOD_NAME(self, e):
    cron_file = self.get_cron_file(e)
    if cron_file is None:
        raise Unfixable("no crontab usual location found (%s)"%str(self.crontab_locs))
    s = self.format_entry(cron_file, e)
    new = False
    if os.path.exists(cron_file):
        with open(cron_file, 'r') as f:
            new = f.readlines()
            found = False
            for line in new:
                if s == line[:-1]:
                    found = True
                    break
            if not found:
                new.append(s+'\n')
    else:
        new = [s+'\n']
    if not new:
        raise ComplianceError("problem preparing the new crontab '%s'"%cron_file)
    pinfo("add entry '%s' to '%s'"%(s, cron_file))
    with open(cron_file, 'w') as f:
        f.write(''.join(new))
    self.activate_cron(cron_file)