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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 _advance_operation_time(self, operation_time):
 """Internal operation time helper."""

        if self._operation_time is None:
            self._operation_time = operation_time
        elif operation_time is not None:
            if operation_time > self._operation_time:
                self._operation_time = operation_time