Tutorial review comments

Volker reviewed the tutorial section in the Python client library SDK and made many comments. Some of those comments suggest changes to the beer sample application. The comments note items of varying severity. For example, one of the comments says that the sample application won't run without the addition of a couple of lines of code.

This task is to review the comments. Then, if needed, update & test the sample code in Github, and then update the SDK documentation to match the sample code.

Attachment: My copy of Volker's review comments. In my copy I checked off the comments that I updated in the documentation.