module test {
    namespace "urn:ietf:params:xml:ns:yang:ietf-isis";
    prefix isis;
    typedef isis-instance-state-ref {
        type leafref {
            path "/isis-prefix-ipv4-std/"
            +"default-metric";
        }
    }
    container isis-route-content {
        leaf metric {
            type isis-instance-state-ref ;
        }
    }
    container isis-prefix-ipv4-std {
        leaf default-metric {
            type string;
        }
    }
}