Re: [O] Bug: python babel does not support hlines as mentioned in docs

[Lennart Fricke]

It is not exactly a missing value. The list looks like 
((v,v),None,(v,v)). v for value.
Missing values are rather like ((v,v),(None,None),(v,v)).
At the moment i can not think of a use case of controlling this translation.
But i have to dig deeper in the translation process of the nested list 
to the org-table, to get a clear picture.
For example i don't know what happens to lists with diffrent number of 
elements like ((v,v,v),v,(v,v)).

Semantics for missing values etc. might be better handled in the python 
code and translated there.
But customizing the object hline is mapped from and to is a good idea.

Best regards
Lennart