mozilla/appsync — comment on commit 06c43c3c8431fe8259b3d164bc2fefce124297ee
File:  line 0
By ianb:

well, I do `.lower()`, so I'd have to default to '' or something to avoid an error (or an extra test), and application/octet-stream seemed like a reasonable default instead of just '' (though they would both have identical effects in this code).