def getall(self):
        try:
            spec = {'data': {'$exists': 1}}
            fields = {'_id': 0}
            sort = [('tid', 1)]
            cur = self.db.docs.find(spec, fields, sort=sort)
        except Exception as e:
            raise DatabaseException(e)
        return [Document(**row) for row in cur]
async def pre_process(self, message, data):
        """
        context language variable will be set each time when update from 'process_update_types' comes
        value is the result of 'get_user_language' method
        """
        self.context_lang.set(await self.get_user_language(obj=message))