44. Bus Error Checker

How do you plan to solve it?

/*Write your code here*/
module error_checker_xz(
    input wire [7:0] bus, 
    output wire all_known, 
    output wire has_unknown, 
    output wire [7:0] bus_if_known
);
    wire any_xz = (^(bus^bus)) === 1'bx;
    assign has_unknown = any_xz; 
    assign all_known = ~any_xz; 
    assign bus_if_known = {8{all_known}} & bus; 
endmodule