Function surface_smile_iv_at_delta 

pub fn surface_smile_iv_at_delta<S: SurfaceSmile + ?Sized>(
    smile: &S,
    market: &SurfaceMarketContext,
    absolute_delta: f64,
    wing: OptionType,
    convention: SurfaceDeltaConvention,
    model: PricingModel,
    policy: SurfaceSmileDeltaSelectionPolicy,
    listed_strikes: &[f64],
) -> Result<f64, FerroRiskError>