44. Bus Error Checker

How do you plan to solve it?

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