Trying to close an option based on the underlyinh price. I have a code here, but I don't think that this is the right way to do it:

if (self.Securities[self.equity_symbol].Price  < self.option_symbol.UnderlyingLastPrice):
        self._buyTicket = self.Buy(self.option_symbol.Symbol,  10) 

I want the code above to be always true, not only in one day. It is similar to creating an order event, but the condition is on the underlying price instead of the option price itself.