The class config_parser.py contains all the parsing routines used to handle loading and saving test.config files. The low level parsing functions are implemented in the file parser module. Only the loading functions are used in the playlist generation.
A small utility class gpPathHandler is used to handle mapping filenames to absolute path and easing path handling in general.
Dialog boxes and file requesters are implemented by the Tkinter library modules Dialog.py and FileDialog.py.
What the playlist creation module first does is that it initializes the GUI with test.config file contents. Then it tries to load the test.items file with the help of the items_parser class. The contents of this file are used to initialize test.items data. Next it tries to load the playlist file with the help of the playlist_parser class. The playlist data structures are intialized from this file.
After this it handles GUI callback procedures for various buttons and saves test.items and playlist file when requested. The code to implement the random test items and playlist creation tasks is really straithforward. Most difficult parts of this module are the error checking parts which handle malformed input files with grace.