class A: value = 'OK' b = Uplink()
class X: y = Uplink()
class Y: x = Unique(X) z = Uplink()
class R2: d = Uplink()
class F: value = Uplink()
class B: zaa = Collection(A) c = Uplink()
class L2: d = Uplink()
class B: a = Uplink()
class A: b = Uplink()
class Small: value = 'Okay' big = Uplink()
class Down: up = Uplink(reusing_by=['id'])
class D: l = Uplink() r = Uplink()
class A: a = 0 b = Uplink()
class Unit: name = '' type = '' squad = Uplink()
class Squad(object): name = '' units = Collection(Unit) leader = Unique(Hero) player = Uplink()
class Hero(object): epic_name = '' squad = Uplink()