Process updates received from long-polling.

        :param updates: list of updates.
        :param fast:

async def _process_polling_updates(self, updates, fast: typing.Optional[bool] = True):
        """
        Process updates received from long-polling.

        :param updates: list of updates.
        :param fast:
        """
        need_to_call = []
        for responses in itertools.chain.from_iterable(await self.process_updates(updates, fast)):
            for response in responses:
                if not isinstance(response, BaseResponse):
                    continue
                need_to_call.append(response.execute_response(self.bot))
        if need_to_call:
            try:
                asyncio.gather(*need_to_call)
            except TelegramAPIError:
                log.exception('Cause exception while processing updates.')