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 x_z = (^(bus^bus)) === 1'bx;
assign all_known = ~x_z;
assign has_unknown = x_z;
assign bus_if_known = all_known ? bus : 8'h00;
endmodule