def test_list():
h = Holder(items=list())
h.items.append(LittleItem(c='a'))
h.items.append(BigItem(a='a', b='b'))
h_js = h.dict()
print(h_js)
try:
h2 = Holder(**h_js)
except ValidationError as e:
print(e)
assert False
assert h == h2
