Raised in hackathon discussion of uncertainties pull request (one of the main points of this issue is to be able to get that pull request through as is, and handle future "nice to haves" here)

If you look in hgvs.utils.position.get_start_end there are lots of isinstance calls, because of the different handling of HGVS spec positions.

Reece wonders whether there is a single representation (eg handling offsets) that can handle everything.

Perhaps another option is to make a class hierarchy to handle the specifics, if one model can't handle them all.