Code review comment for lp://qastaging/~cjwatson/command-not-found/python3

47 + if key is not bytes:

I think you meant isinstance() here

74 - (PACKAGE, BASENAME_PATH) = range(2)
75 + (PACKAGE, BASENAME_PATH) = list(range(2))

299 - (SOFT, HARD) = range(2)
300 + (SOFT, HARD) = list(range(2))

(and some more), those changes seem unneeded, am I missing something?

Otherwise, wow, lots of old code that brings back memories, great work in porting that to python3! :)