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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 update(self, branch='default'):
        '''
        Ensure we are using the latest revision in the hg repository
        '''
        log.debug('Updating hg repo from hg_pillar module (pull)')
        self.repo.pull()
        log.debug('Updating hg repo from hg_pillar module (update)')
        self.repo.update(branch, clean=True)