python报错cannot unpack non-iterable NoneType object求解决qwq

import cv2
from cvzone.HandTrackingModule import HandDetector

cap = cv2.VideoCapture(0)
cap.set(3, 1280)
cap.set(4, 720)

detector = HandDetector(detectionCon=0.8)

while True:
    success, img = cap.read()
    img = detector.findHands(img)
    lmList, bboxInfo = detector.findPosition(img)
    cv2.imshow("Image", img)
    cv2.waitKey(1)

lmList, bboxInfo = detector.findPosition(img)
这句报错

detector.findPosition(img)返回一个值，但是有两个变量去接受这个，所以报错

这个说是写下一个lm列表