Hello, Im debugging my algo, that buy SPY ETF and SPY option based on the value of VIX. When VIX is higher than 35 the algo look for contracts options on SPY and buy one of them based in the conditions that are specified in self.BuyCall() function. 

I'm receiving this error message, in the first time that the algo would buy the option:

Backtest Handled Error: Unable to submit order with id -10 which quantity (0.3) is less than lot size (1).

Someone can help on this? I don't figure out what this message means? The error is between lines 101-106 that is where the logic to buy the call option is.