Must load all the entities it needs from cache, and
        return ``False`` if it could not find all of them.

def _load_entities(self):
        """
        Must load all the entities it needs from cache, and
        return ``False`` if it could not find all of them.
        """
        if not self._chat_peer:
            return True  # Nothing to load (e.g. MessageDeleted)

        self._chat, self._input_chat = self._get_entity_pair(self.chat_id)
        return self._input_chat is not None