code: def nickmask(prefix: str, kwargs: Dict[str, Any]) -> None:
      
      if "!" in prefix and "@" in prefix:
          # From a user
          kwargs["nick"], remainder = prefix.split("!", 1)
          kwargs["user"], kwargs["host"] = remainder.split("@", 1)
      else:
          # From a server, probably the host
          kwargs["host"] = prefix
docs: store nick, user, host in kwargs if prefix is correct format