code: def __run(self):
  		
  		self.interval_start = time.time()
  		while self.status != STOPPED:
  			if self.status == RUNNING:
  				self.current_interval_duration = time.time() - self.interval_start
  
  			# If max_duration is set, stop the clock if it is reached
  			if self.max_duration and self.time > self.max_duration:
  				self.status == STOPPED
  
  			# One refresh per millisecond seems enough
  			time.sleep(0.001)
docs: Internal function that is run in a separate thread. Do not call 
  		directly.