def __init__(self, timer: Optional[TimerService]=None):
    self._get_current_time = (timer.get_current_time if timer else perf_counter)
    self._start_time = self._get_current_time()
def __init__(self, timer: Optional[TimerService]=None):
    self._get_current_time = (timer.get_current_time if timer else perf_counter)
    self._start_time = self._get_current_time()