code: def split(self, amt):
          
          ratio = abs(amt / self.qty)
          t1 = Trade(self.tid, self.ts, amt, self.px, fees=ratio * self.fees, **self.kwargs)
          t2 = Trade(self.tid, self.ts, self.qty - amt, self.px, fees=(1. - ratio) * self.fees,
                     **self.kwargs)
          return [t1, t2]
docs: return 2 trades, 1 with specific amt and the other with self.quantity - amt