Missing buy/sell variable statements during backtest (amibroker)

While doing backtest of the following script in amibroker, I get 'missing buy/sell variable assignment' error, though I have assigned buy/sell variables in the script.

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function isBuyCond()
return (C[BarCount-2] > O[BarCount-2]);

function isSellCond()

return (C[BarCount-2] <= O[BarCount-2]);

if (isSellCond())
Sell = 1;

if (isBuyCond())
Buy = 1;

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Basically with the above strategy, I am trying to generate buy/sell signals based on the last candle. If candle is green, then set BUY to True; if candle is red, set SELL to true.

Please let me know if I am missing something

Missing buy/sell variable statements during backtest (amibroker)