[Vala] HashTable.lookup should return "V?"

[tecywiz121 <tecywiz121 hotmail com>]

If I understand the entire "non-nullable" type concept of vala, then
only variables with a "?" should be nullable at least in theory,
correct?

If that is the case, then I believe that HashTable<K, V>.lookup should
in fact return a "weak Texture?" as opposed to a "weak Texture" since if
it can't find a key, it returns null.

Thanks,
Sam