class LightLCServer(Model):
    ID = ModelId(None, 0x130F)
    
    ELEMENT = ModelElement.LIGHT_LC
    EXTEND = {
        ModelElement.LIGHT_LC: (GenericOnOffServer,),
    }


class LightLightnessServer(Model):
    ID = ModelId(None, 0x1300)

    ELEMENT = ModelElement.MAIN
    EXTEND = {
        ModelElement.MAIN: (GenericPowerOnOffServer, GenericLevelServer),
        ModelElement.LIGHT_LC: (LightLCServer,),
    }

light_lightness is light_lc.corresponding(LightLightnessServer, ModelElement.MAIN)
light_lc is light_lightness.corresponding(LightLCServer, ModelElement.LIGHT_LC)

def diff(lhs_model, rhs_model):
    assert type(lhs_model) == type(rhs_model)
    
    # only if we own the subscription list
    if lhs_model.root:
        for missing_subscription in (
            lhs_model.subscriptions - rhs_model.subscriptions
        ):
            yield (StateAction.ADD, "subscriptions", missing_subscription)
    
        for extra_subscription in rhs_model.subscriptions - lhs_model.subscriptions:
            yield (StateAction.DEL, "subscriptions", missing_subscription)
     
    if lhs_model.publication != rhs_model.publication:
        yield (StateAction.SET, "publication", lhs_model.publication)

    for missing_bind in lhs_model.app_keys - rhs_model.app_keys:
        yield (StateAction.ADD, "app_keys", missing_bind)

    for extra_bind in rhs_model.app_keys - lhs_model.app_keys:
        yield (StateAction.DEL, "app_keys", extra_bind)

    for attribute in lhs_model.__attrs__:
        lhs_value = getattr(lhs_model, attribute.name)
        rhs_value = getattr(rhs_model, attribute.name)

        if lhs_value != rhs_value:
            yield (StateAction.SET, attribute.name, lhs_value)

def diff(lhs_element, rhs_element):
    for lhs_model, rhs_model in zip(
        sorted(lhs_element.models.values()), sorted(rhs_element.models.values())
    ):
        for (action, state, value) in lhs_model - rhs_model:
            yield Diff(lhs_element.index, type(lhs_model),
                       state, action, value)
            
def diff(lhs_node, rhs_node):
    for lhs_element, rhs_element in zip(lhs_node.elements, rhs_node.elements):
        yield from lhs_element.diff(rhs_element)

Diff(element=0, model=GenericLevelClient, state='app_keys',
     action=ADD', value=1)
Diff(element=0, model=GenericLevelClient, state='publication',
     action=SET, value=Publication(publish_address=49154, app_key_index=1, ...))
Diff(element=0, model=LightLightnessServer, state='app_keys',
     action=ADD, value=1)
Diff(element=0, model=LightLightnessSetupServer, state='subscriptions',
     action=ADD, value=49152)
Diff(element=0, model=LightLightnessSetupServer, state='subscriptions',
     action=ADD, value=49154)
Diff(element=1, model=GenericLevelClient, state='app_keys',
     action=ADD, value=1)
Diff(element=1, model=GenericLevelClient, state='publication',
     action='SET', value=Publication(publish_address=49156, app_key_index=1, ...)
Diff(element=1, model=LightCTLTemperatureServer, state='app_keys',
     action=ADD, value=1)
Diff(element=1, model=LightCTLTemperatureServer, state='subscriptions',
     action=ADD, value=49156)