Function decide 

pub async fn decide(
    model: &dyn DecisionModel,
    sop: &Sop,
    spec: &SopDecisionSpec,
    event: &SopEvent,
) -> SopDecision

Ask model about event for sop and resolve the answer against the SOP’s [decision] spec. Never errors: every model failure resolves to the spec’s fail-closed outcome with the failure in rationale.