The market functionfnGetVolume calculates volume of a market.
Notes:
- A market function is any VTS function that accepts a symbol as a parameter and returns a positive number.
- The fnGetBestMarket function calls a market function for all selected symbols and returns the symbol with the highest score.
- Although a market function can be dragged and dropped onto a drawing, typically this is not done. Instead the market function is selected in Function section of the fnGetBestMarket function