Read update from stream and deserialize it.

        :param bot: bot instance. You an get it from Dispatcher
        :return: :class:`aiogram.types.Update`

async def parse_update(self, bot):
        """
        Read update from stream and deserialize it.

        :param bot: bot instance. You an get it from Dispatcher
        :return: :class:`aiogram.types.Update`
        """
        data = await self.request.json()
        update = types.Update(**data)
        return update