I bought "Agile Artificial Intelligence in Pharo" and am using Pharo 8.0 64-bit.  In the book it says you can download the source using:

Metacello new
  baseline: 'AgileArtificialIntelligence';
  repository: 'github://Apress/agile-ai-in-pharo/src';
  load.

Then it times out with:
"MCSmalltalkhubRepository(MCRepository)>>error:"
self

Could not load Athens-SVG-PeterUhnak.17.mcz:
ZnHttpUnsuccessful: 503 Service Temporarily
Unavailable

I am fairly new to Pharo and run into problems with documentation being old, for example, Pharo By Example. I realize it is difficult to keep books updated with the many changes in an active project. I'm fine with that.

However, how can a just published book have the source listed in its pages, but then not have it available?