docs: def reqPnL(self, account: str, modelCode: str = '') -> PnL:
          """
          Start a subscription for profit and loss events.
  
          Returns a :class:`.PnL` object that is kept live updated.
          The result can also be queried from :meth:`.pnl`.
  
          https://interactivebrokers.github.io/tws-api/pnl.html
  
          Args:
              account: Subscribe to this account.
              modelCode: If specified, filter for this account model.
          """
          key = (account, modelCode)
          assert key not in self.wrapper.pnlKey2ReqId
          reqId = self.client.getReqId()
          self.wrapper.pnlKey2ReqId[key] = reqId
          pnl = PnL(account, modelCode)
          self.wrapper.pnls[reqId] = pnl
          self.client.reqPnL(reqId, account, modelCode)
          return pnl