Function resolved_bond_view 

fn resolved_bond_view<T>(
    bond: &FixedRateBond,
    market: &MarketContext,
    security_spread: Option<&str>,
    repo_key: Option<&str>,
    read: impl FnOnce(&PricingView<'_, f64>) -> Result<T, PricingError>,
) -> Result<T, PricingError>

The curves a fixed-rate bond reads for a spread measure: its currency’s discount, overlaid by the security spread under security_spread where one is named, or financed on the repo curve under repo_key.