oh, it’s definitely callable - I’ve already put a lambda in the definition of train_dataset but that doesn’t seem to be the source of the error at all.
The actual problem is a bit simple, but I can’t seem to get my head around it at all:-
https://www.toptal.com/developers/hastebin/uwanewivul.py 8
very simply, in my own script ,train_dataset seems to change its value automatically after a few lines of code and comments none of which actually reference it directly