44. Bus Error Checker

How do you plan to solve it?

/*Write your code here*/
module error_checker_xz(
    input [7:0] bus,
    output all_known, has_unknown,
    output [7:0] bus_if_known
);

    wire any_xz = (^(bus ^ bus)) === 1'bx;

    assign has_unknown  = any_xz;
    assign all_known = ~has_unknown;
    assign bus_if_known = (all_known)?bus:0;

endmodule