plugin XEP-0444: complete implementation: "Message Reactions" implementation is now working and updating history. The `message_reactions_set` bridge method can be used by frontend to `replace`, `add`, `remove` or `toggle` reactions. History is properly updated, and signal are sent when necessary.

from typing import Optional

from twisted.words.xish import domish


class BaseError(Exception):
    namespace: str
    condition: str
    text: Optional[str]
    textLang: Optional[str]
    appCondition: Optional[domish.Element]

class StanzaError(BaseError):
    ...