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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 start_timer(self):
 """ This is a low-level method that is called by pywbem at the begin of an operation. It starts the measurement for that operation, if statistics is enabled for the connection. A subsequent invocation of :meth:`~pywbem.OperationStatistic.stop_timer` will complete the measurement for that operation and will update the statistics data. """

        if self.container.enabled:
            self._start_time = time.time()
            if not self._stat_start_time:
                self._stat_start_time = self._start_time