Running a python program as main...

[waltbrad]

Stumbling through Mark Lutz's "Programming Python 3rd",  he gives an
example of a program that will automatically configure environment
settings and launch other programs.  Then he gives an example of
running this program. On  his command line he types:

C:\...\PP3E>Launcher.py

and this begins the program.  Doesn't work for me. I have to type:

C:\...\PP3E>python Launcher.py

Is this a typo on his part or has he configured his settings in such a
way that the command line will automatically associate the extension
with the program? (If so, he didn't mention this in his book).