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
);

assign all_known = (&(bus ^ ~bus) === 1'b1);
assign bus_if_known = all_known ? bus : 8'd0;
assign has_unknown = ~all_known;

endmodule