Function active_rules 

pub fn active_rules<'a>(
    dtcs: &[Dtc],
    spec: Option<&'a VehicleSpec>,
) -> Vec<&'a DiagnosticRule>

Find diagnostic rules that fire for the current set of DTCs.

Rules fire based on triggers (BR-4.2):

• DtcPresent: fires when a specific DTC code is in the list
• DtcRange: fires when any DTC in the range is present