import test

entity Collection:
end

implement Collection using test::none

Collection.items [0:] -- test::Item.collection [0:]

c1 = Collection()

t1 = test::Item(name="t1", collection=c1)
t2 = test::Item(name="t2", collection=c1)
t3 = test::Item(name="t3", collection=c1)

c1a1 = test::list_id(c1.items)
c1a2 = test::unwrap_list(c1.items)

s1 = "xxx"
s2 = test::makelist(s1)

