@pytest.fixture
def credentials(request):
    value = request.config.getoption('credentials')
    if request.cls:
        with open(value) as json_file:
            request.cls.credentials = json.load(json_file)
    return value
@pytest.fixture
def credentials(request):
    value = request.config.getoption('credentials')
    if request.cls:
        with open(value) as json_file:
            request.cls.credentials = json.load(json_file)
    return value