Emits the start requested signal for this timer, effectively starting
        its internal timer.
        
        :param      interval | <int>

def start(self, interval=None):
        """
        Emits the start requested signal for this timer, effectively starting
        its internal timer.
        
        :param      interval | <int>
        """
        # update the interval value
        with QtCore.QReadLocker(self.__lock):
            if interval is None:
                interval = self.__interval
            else:
                self.__interval = interval
        
        # request the timer to start
        self._startRequested.emit(interval)