def onlyPy3(test):

    @functools.wraps(test)
    def wrapper(*args, **kwargs):
        msg = "{name} requires Python3.x to run".format(name=test.__name__)
        if not six.PY3:
            raise SkipTest(msg)
        return test(*args, **kwargs)
    return wrapper
Making list of fetching urls from exchanges.
dataset/ETHPy150Open shazow/urllib3/test/__init__.py/onlyPy3--crossover with--dataset/ETHPy150Open yinhm/datafeed/datafeed/providers/nasdaq.py/NasdaqListFetcher._fetching_urls