title: Need skeleton code to call Excel VBA from PythonWin
body: <p>I need to invoke a VBA macro within an Excel workbook from a python script.  Someone else has provided the Excel workbook with the macro.  The macro grabs updated values from an external database, and performs some fairly complex massaging of the data.  I need the results from this massaging, and I don't really want to duplicate this in my Python script, if I can avoid it.  So, it would be great if I could just invoke the macro from my script, and grab the massaged results.</p>
  
  <p>Everything I know about COM I learned from "Python Programming on Win32".  Good book, but not enough for my task at hand.  I searched, but haven't found any good examples on how to do this.  Does anyone have any good examples, or perhaps some skeleton code of how to address/invoke the VBA macro?  A general reference (book, web link, etc) on the Excel COM interfaces would also help here.  Thanks.</p>