Buy - MFI is trending upward
Sell - MFI is trending downward
Parameters available:
Period - period of MFI
t - the minimum slope of the moving average of MFI when it is trending
Slope - the slope of the MFI when it is trending
MA Period - the number of periods used for moving average calculation
Rule type - please refer to 140 for details
Data type - please refer to 141 for details