Steps to reproduce

1. Add an object with a bot attribute to e.g.chat_data and persist it

2. Change the bots token and restart the updater

Expected behaviour

The reloaded bot should have the new token.

Actual behaviour

The bot in the loadedchat_data still has the old token. Similar for the other bot attributes

Proposed solution

1. Remove__reduce__ fromBot , as we don't want to encourage pickling bots

2. Add static methodsreplace_bots(object) andset_bots(objects, bot) (or other naming) toBasePersistence, wherereplace_bots implements the logic to replace everyBot instance in an object, be it a dict, a list, a custom object … with some special placeholderBOT_INSTANCE or whatever andset_bots in turn replacesBOT_INSTANCE with the given bot. To makeget_*_data andupdate_*_data use those, we have several options:

   1. Just call them inget/update_. Custom subclasses ofBasePersistence will have to adjust.
   2. Add a__new__ method to make theget/update_ methods call the methods under the hood. that way custom subclasses don't need to change anything
   3. Add methodsget/update_*_replace_bot, which callset/replace_bots and before/afterget/update_*. Use those inUpdater. This way, custom classes also don't need to be changed.

   don't know, whats better …

3. Alternatively to passing the bot toset_bots, we could addset_bot toBasePersistence so that we can useself.bot inset_bot. That would save us from having to passbot toget_* as well