[PyQt] PyQt API 2: equivalent of Null QVariant?

[TP]

Phil Thompson wrote:

> API v1 will be supported until PyQt5 or Python v4.

Is it contractual? Why Python v4? It seems to me that nobody knows when 
Python v4 will appear.
Anyway, it seems to be a problem that API2 does not support NULL, even if it 
corresponds to side cases (as mine).

Thanks,

Julien