Timer class for timings

Timer

def test_timer(timer, duration = 1):
    timer.enable()
    time.sleep(1)
    timer.disable()
    print(timer.get_elapsed())
timer = Timer()
test_timer(timer)
class Timer(object):
    def __init__(self, time=time.time):
        self.time = time
        self.elapsed = 0
        self.start = None
    def enable(self):
        if self.start is not None: raise ValueError
        self.start = self.time()
    def disable(self):
        if self.start is None: raise ValueError
        period = self.time() - self.start
        self.elapsed += period
        self.start = None
    def get_elapsed(self):
        if self.start is None:
            return self.elapsed
        else:
            return time.time() - self.start + self.elapsed
timer = Timer()
test_timer(timer)
ptimer = Timer(time.process_time)
test_timer(ptimer)