I understand the reason for `_init_keys`. But you've hard-coded exposure here. That's *not* generic. Admittedly, it's because we log it in the `__init__` and store the logged version. So...either fix that as part of this PR too (and add logs whenever exposure is used / fix the hard-coded exposure or offset only) or only check for exposure in CountModel. That's my main point. My other point is that if you're going to introduce those changes in this (bug fix) PR, then go the whole nine yards and implement the `_get_keys` or whatever. This could've been a quick two line fix to close the bug but now I'd like to see the other issues fixed in this PR, if we're going to start the other changes.