@real_memoize
def is_darwin():
    return sys.platform.startswith('darwin')
Test assertWarns works when used on an instance method.
dataset/ETHPy150Open saltstack/salt/salt/utils/__init__.py/is_darwin--crossover with--dataset/ETHPy150Open nlloyd/SubliminalCollaborator/libs/twisted/trial/test/test_assertions.py/WarningAssertionTests.test_assertWarnsOnMethod