code: async def _retrieve_messages_before_strategy(self, retrieve):
          
          before = self.before.id if self.before else None
          data = await self.logs_from(self.channel.id, retrieve, before=before)
          if len(data):
              if self.limit is not None:
                  self.limit -= retrieve
              self.before = Object(id=int(data[-1]['id']))
          return data
docs: Retrieve messages using before parameter.