AttributeError: module 'cv2.cv2' has no attribute 'cudacodec'

[i3587616]

Expected behaviour

i success install pip install opencv-contrib-python

but when
cv2.cudacodec.createVideoWriter("tmp", (128, 128), 30)
it info AttributeError: module 'cv2.cv2' has no attribute 'cudacodec'
why ?
opencv-contrib-python contain cudacodec but why no module

[i3587616]

i am in china,can who help me,my english is not well .but i think i tell the problem exactly