def test_Map_is_monoidal():
m = Map({'a': 10})
n = Map({'b': 7})
o = Map({'c': 4})
assert Map.mappend(m, Map.mappend(n, o)) == \
Map.mappend(Map.mappend(m, n), o)
def test_Map_mappend():
m = Map({'a': 10})
n = Map({'b': 7})
assert m.mappend(n) == Map({'a': 10, 'b': 7})