我想讀取一個視頻文件，將其分成單獨的幀，將每個幀的大小調整為最大寬度，然后檢索最終圖像的寬度和高度。我試過這個：為真：vs = cv2.VideoCapture(args["video"])# grab the frame from the threaded video stream and resize it# to have a maximum width of 400 pixelsframe = vs.read()frame = imutils.resize(frame, width=400)# grab the frame dimensions and convert it to a blobw, h = cv.GetSize(frame)但我得到：Traceback (most recent call last):  File "real_time_object_detection.py", line 52, in <module>    frame = imutils.resize(frame, width=400)  File "/home/pi/.virtualenvs/cv/lib/python3.5/site-packages/imutils/convenience.py", line 69, in resize    (h, w) = image.shape[:2]AttributeError: 'tuple' object has no attribute 'shape'為什么它會抱怨一行imutils/？我該怎么做？