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