message: hotfix: call isOpened() in python bg sub tutorial
diff: @@ -18,7 +18,7 @@ else:
  ## [capture]
  capture = cv.VideoCapture(cv.samples.findFileOrKeep(args.input))
  -if not capture.isOpened:
  +if not capture.isOpened():
  print('Unable to open: ' + args.input)
  exit(0)
  ## [capture]
  