Below is a solution I came up with for executing a Python function from a VBScript function. Does a better method exist?
http://www.savvydiadempysolutions.com/index.php?tab=script&topic=script-call-python-function-from-vb...
The procedure I used was to call a Python script from VBS using ScriptStart(), and then pass a string as a DIAdem global variable to the Python script that contains a Python call to execute a Python function. The global DIAdem string is executed in Python using the Python exec() command.