public long UpdatePosition( string ticker, long quantity )
 {
     IPosition pos = new Position();
     pos = pos.GetPosition( ticker );
     pos.Quantity += quantity;
     return pos.Quantity;
 }
 public long GetQuantity( string ticker )
 {
     IPosition pos = new Position();
     pos = pos.GetPosition( ticker );
     return pos.Quantity;
 }