You’ll need to look through the objections to this proposal and answer them. Why are the problems no longer problems? Are there new advantages that weren’t known about when that was written?
I think this is quite an unfair burden to OP. The PEP lists no objections, the commit changing the status to “Deferred” lists no reasons. The PEP doesn’t even have a “Discussions-To” header. After five years it seems appropriate to start a new discussion, instead of digging through three years worth of mailing list archives. (The time between the creation of the PEP and the change to “Deferred”.)