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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_connection(self):
 # pylint: disable=C0103 """ Closes serial port connection. :return: Nothing """

        if self.port:
            self.stop()
            self.logger.debug("Close port '%s'" % self.comport,
                              extra={'type': '<->'})
            self.port.close()
            self.port = False