in webcam_demo.py 'NoneType' object has no attribute 'copy'

After running webcam_demo.py on tensorflow v1.5 (cpu not gpu) I got the error: Traceback (most recent call last): File "webcam_demo.py", line 116, in <module> show_webcam(mirror=True) File "webcam_demo.py", line 72, in show_webcam origImg = img.copy() AttributeError: 'NoneType' object has no attribute 'copy'