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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 close(self):
        "Close the shelve object, which is needed for data consistency."
        if self.is_open:
            logger.info('closing shelve data')
            try:
                self.shelve.close()
                self._shelve.clear()
            except Exception:
                self.is_open = False