UserAgent: Mozilla/5.0 (X11; CrOS x86_64 9334.72.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/58.0.3029.140 Safari/537.36
Platform: 9334.72.0 (Official Build) stable-channel cyan

Steps to reproduce the problem:
Instructions at https://www.chromium.org/chromium-os/how-tos-and-troubleshooting/install-software-on-base-images
fail

1. Enable developer mode 
2. sudo -i
3. dev_install

Exits with error message "/usr/local/bin/python2.7: error while loading shared libraries: libpython2.7.so.1.0: cannot open shared object file: No such file or directory"

Whereas:

1. Enable developer mode 
2. sudo su -
3. dev_install

Success!

What is the expected behavior?

What went wrong?
The instructions at https://www.chromium.org/chromium-os/how-tos-and-troubleshooting/install-software-on-base-images said `sudo -i` where the should say `sudo su -`.

An explanation is available on a post to chromium-os-dev:
https://groups.google.com/a/chromium.org/d/msg/chromium-os-dev/pvl6gOMKuPw/QjLPMSzu5mkJ

Did this work before? N/A 

Chrome version: 58.0.3029.140  Channel: n/a
OS Version: 9334.72.0
Flash Version: Shockwave Flash 25.0 r0