stopWatch.py

import time


class StopWatch:

    def __init__(self, func=time.perf_counter):
        self.elapsed = 0.0
        self._start = None
        self._func = func
        self.maxTime = 10000000

    def start(self):
        if self._start is not None:
            raise RuntimeError('Already started')
        self._start = self._func()

    def stop(self):
        if self._start is None:
            raise RuntimeError('Not started')
        end = self._func()
        self.elapsed += end - self._start
        self._start = None

    def counter(self):
        while self.maxTime > 0:
            self.maxTime -= 1

    def __exit__(self, *args):
        self.stop()

    @property
    def elapsedTime(self):
        return self.elapsed


sw = StopWatch()
sw.start()
time.sleep(4)
sw.stop()
print(sw.elapsedTime)