Class properties return NoneType instead of nil

[vishnevskiy]

If a class property such as

@property
def my_fn(self):
    return None

Is access via Lua and the return is None then you get None itself rather than nil.

[scoder]

The handling of "nil" in Lua is not always obvious. In some cases, nil has a special meaning, so returning nil from Lupa can be ambiguous and may prevent users from figuring out what has actually happened (is it an error case or did someone return None or nil on purpose?)

I admit that the cases where Lupa returns either None or nil are not all thoroughly thought out. It's worth some more investigation. Any help is appreciated.

[scoder]

None/nil handling has been redone in Lupa 1.0.