Theres no such thing as pySource. The entire tutorial is obolete as it builds on different python implemnetation tahts really used.
Dont use the tutorial it teaches you nothing. Even tough the python in use does build on the same core idea. Its however completely different in practice. Its not just old its bade on a python plug completely developped by a fifferent crowd.
The entire nevironment is different. Read some other tutorial,
Aslo not epySource in the demo is MEL not python. And it doent exist its part of the cg toolkit python implemnantation. As such it doent exist anymore.
Anyway the entire tutorial is just as uninformative as well. It teaches you basically nothing of interest. As everything thats there you can echoffrom amya in less thatn teh time it takes you to read the tutorial.
PS: its just not old it predates maya python interface. Ita like finding a tutorial on how to make webpages that pedates any browser.