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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 clean(self, suffixes=None):
 """ Remove all persistence-related files from the directory. """

        if suffixes is None:
            suffixes = [DONE_SUFFIX, LOCK_SUFFIX, PART_SUFFIX]

        for suffix in suffixes:
            listing = self.working_context.get_listing(suffix)
            for filename in listing:
                self.working_context.remove(filename)