Hide input cells #32. That would make the ability to mix hidden python stuff with purposefully displayed python. I struggled with this, too. My first attempt was for a talk at EuroPython 2014 (Brainwaves for Hackers) where I hacked the live_reveal extension to interpret skip (from the slideshow-toolbar) as hide input.
An ISO file is a complete copy of a CD or DVD. You can create ISO images yourself or download them from the Internet. For example, Linux distributions offer freely downloadable ISO files that you can burn to disc. You can use an ISO image in a variety of ways. The ISO file itself is a backup of a disc, so you can use the ISO file if you ever lose or damage the original disc CDs Are Not Forever: The Truth About CD/DVD Longevity, Mold & Rot .
Copying a disc to ISO format is called ripping, and allows you to create perfect backups of any disc in single files. Make sure your drive supports the disc you want to rip. For example, you cannot rip a Blu-ray disc in a DVD drive, but you can rip a DVD disc in a Blu Ray drive.. Download an ISO compiler program. There are a variety of programs that can be downloaded for free or purchased that will allow you to create ISO files from a CD, DVD, or Bluray Disc (BD). Popular programs include MagicISO, ISO Recorder, and ImgBurn.