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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):
 """Closes the VISA session and marks the handle as invalid. """

        try:
            logger.debug('%s - closing', self._resource_name,
                         extra=self._logging_extra)
            self.before_close()
            self.visalib.close(self.session)
            logger.debug('%s - is closed', self._resource_name,
                         extra=self._logging_extra)
            self.session = None
        except errors.InvalidSession:
            pass