Checking for dlls in ctypes

[Wanderer]

I'm trying to write some code that will load one of three dll depending on the one available. I've tried the code below, but it doesn't work. The try except doesn't catch the exception. Is there a way to do this?

        try:
            self.dll = windll.pvcam64
        except:
            print "No pvcam64"
            try:
                self.dll = windll.pvcam32
            except:
                print "No pvcam32"
                try:
                    self.dll = windll.pvcam
                except:
                    print "No pvcam"
                    return
                else:
                    print "installed pvcam"
            else:
                print "installed pvcam32"
        else:
            print "installed pvcam64"