The SMAStrategy strategy based on two SMA (Simple moving average) : sma with time period 10 and sma with time period 90. The strategy logic can be described as 2 actions: If Sma 10 cross Sma 90 from up to down, then the strategy closes existing short position and open a buy order if long position does not exist If Sma 10 cross Sma 90 from down to up, then the strategy closes existing long position and open a sell order if short position does not exist