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,
    output has_unknown,
    output [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