Disc Crv

Key Disc Crv in Vol Curve refers to an optional yield curve, which is used to discount the various cash flows.
Exceptionally, it is mandatory input in the case when Vol Input = Maturity-Strike and Moneyness = true and Moneyness Spot = true
If it is optional and omitted, the given Forc Crv is used.
Expects an object of type Yield Curve.