Call python from module and receive output
Thanks for the responses.  The basic take-home for me here is to try a simple python script shell_exec first.  Once I did this I was able to quickly see that shell_exec was working as expected.  This in turn led me to my issue which ended up being not really related where I had some minor path issue that were throwing me off.  Perhaps drupalist advice to "try a simple command to make sure shell_exec works, then check the python" will help others with the same issue.

Derek