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Hmm. We can access the queue from every view by creating its interface object like here (a queue is actually an external Redis thing). If you think that this can create repeated code, then we should move it. Now it is only used in this very view, but it is likely to be used in some others in the near future and then we will have repeated code, yes.
Anyway, we cannot create it in extensions, as we need to have the redis sentinel already configured, so it has to be done after core.py is processed... or at least after the part of it in which sentinel is set up.
IMHO creating now more functions functions there on core.py that also must take into account the order in which they're executed and everything is now complicating things. I would keep the queue in account.py as it is for now, BUT first time we need to re-use it on another view, do a refactor and move it to a more appropriate place (core.py).