44. Bus Error Checker

How do you plan to solve it?

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 = ~any_xz;
assign bus_if_known = ~{8{has_unknown}} & bus;

endmodule