codec for byte transparency

[Skaperen]

given "random" bytes in the range from 0 to 255, such as from a file containing machine executable code, i would like to convert this "byte sequence" to str type without applying any UTF-8, or any other, interpretation to it. the following code can do this:

# convert bytes in b to str in s without any encoding
s = ''.join(chr(x)for x in b)

what codec would do the same thing in decode or the exact reverse in encode (when every str character has an ord() value of 255 or lower)?