Leaving aside whether this problem is a good application of this compression trick, I want to say that everyone experimenting with this should stop using `gzip`

Leaving aside whether this problem is a good application of this compression trick, I want to say that everyone experimenting with this should stop using `gzip` and start using `zlib`. If you change the first line from `gzip.compress` to `zlib.compress` you should get the same classifier performance with a 3x speedup.