Function survival_quote_block 

fn survival_quote_block(
    discount: &Curve,
    storage: &Survival,
    hazards: &[f64],
    recovery: Option<f64>,
    rungs: &[Rung],
    fixings: &FixingStore,
    fx: &FxRates,
) -> Result<(Vec<f64>, Vec<Vec<f64>>, JacobianEngine), CalibrationError>

Every rung’s quote read back on the survival curve hazards describes, and its derivative with respect to every segment hazard — the credit form of the quote block, over the same lane loop.