@pytest.fixture(params=[pd.offsets.Hour(2), timedelta(hours=2), np.timedelta64(2, 'h'), Timedelta(hours=2)], ids=str)
def delta(request):
    return request.param
@pytest.fixture(params=[pd.offsets.Hour(2), timedelta(hours=2), np.timedelta64(2, 'h'), Timedelta(hours=2)], ids=str)
def delta(request):
    return request.param