@sig(H/ "b" >> (H/ "a" >> "b") >> t(Maybe, "a") >> "b")
def maybe(default, f, maybe_a):
    return default if maybe_a == Nothing else f(maybe_a[0])
Fetches information of a certain policy_rule.
dataset/ETHPy150Open billpmurphy/hask/hask/Data/Maybe.py/maybe--crossover with--dataset/ETHPy150Open openstack/python-group-based-policy-client/gbpclient/v2_0/client.py/Client.show_policy_rule