AttributeError: 'NoneType' object has no attribute 'shape'

[ShitBro369]

when i run 'real_time_video.py'
error as fllow:(what can i do)
Traceback (most recent call last):
File "C:/Users/Lenovo/PycharmProjects/Emotion-recognition/real_time_video.py", line 29, in
frame = imutils.resize(frame,width=300)
File "D:\anaconda\lib\site-packages\imutils\convenience.py", line 69, in resize
(h, w) = image.shape[:2]
AttributeError: 'NoneType' object has no attribute 'shape'