code: def outlay(self, q):
          
          fee = self.commission(q, self._price * self.multiplier)
          outlay = q * self._price * self.multiplier
          return outlay + fee, outlay, fee
docs: Determines the complete cash outlay (including commission) necessary
          given a quantity q.
          Second returning parameter is a commission itself.
  
          Args:
              * q (float): quantity