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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 _cleanup_old_backups(self, database=None, servername=None):
 """ Cleanup old backups, keeping the number of backups specified by DBBACKUP_CLEANUP_KEEP and any backups that occur on first of the month. """

        self.storage.clean_old_backups(encrypted=self.encrypt,
                                       compressed=self.compress,
                                       content_type=self.content_type,
                                       database=database,
                                       servername=servername)