module ietf-network {
    yang-version 1;
    namespace "urn:ietf:params:xml:ns:yang:ietf-network";
    prefix nd;
    import network {
       prefix "nw";
    }
    grouping xyz {
        leaf network-id-ref {
            type leafref {
                path "/nw:networks/nw:network/nw:network-id";
                require-instance false;
            }
            description
                "A reference to a network-id in base ietf-network module.";
        }
    }
    grouping yzx {
        container hi {
        uses xyz;
        }
    }
    container fine {
        uses yzx;
    }
    container networks {
        leaf network {
            type string;
        }
    }
}