this mean this means that since there's a party that holds true for any usually decodable code someone can give you include the decodable code this property will be true when this profit is true there is also a prefix code with the same lengths so it means that we never need to resort to anything but prefix codes if my said have a very clever scheme to make the bitstream uniquely decodable you might have to look ahead and look and look at many places of decode you can say no need i can use the same encoding length and build a prefix