how to sell a long order position at limit price, instead of opening a short order

[Marinades]

I would like to sell a long position at a set limit, instead of buying a short position with sell. Can anyone help?
Sample code:

def next(self):
    if not self.position:
        self.buy() # buys the long order
        return
    if self.position.is_long:
        self.sell(size=self.position.size, limit=limit)
        return

after the self.sell() and when reaching the next next() the self.position.is_short changes to True, which is not what I want. I would just like to buy and sell long positions.