code: def hookScreenshot(self, numTypes):
          
  
          fn = self.function_table.hookScreenshot
          pSupportedTypes = EVRScreenshotType()
          result = fn(byref(pSupportedTypes), numTypes)
          return result, pSupportedTypes
docs: Called by the running VR application to indicate that it
           wishes to be in charge of screenshots.  If the
           application does not call this, the Compositor will only
           support VRScreenshotType_Stereo screenshots that will be
           captured without notification to the running app.
           Once hooked your application will receive a
           VREvent_RequestScreenshot event when the user presses the
           buttons to take a screenshot.