[Alightment/coordinateReg] AttributeError: 'NoneType' object has no attribute 'prepare'

**I have a problem running the file 'image_infer.py'**
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Error:
PS E:\DataTraining\insightface-master\insightface-master> & "C:/Program Files/Python36/python.exe" e:/DataTraining/insightface-master/insightface-master/alignment/coordinateReg/image_infer.py
loading ./model/2d106det 0
Traceback (most recent call last):
File "e:/DataTraining/insightface-master/insightface-master/alignment/coordinateReg/image_infer.py", line 149, in
handler = Handler('./model/2d106det', 0, ctx_id=7, det_size=640)
File "e:/DataTraining/insightface-master/insightface-master/alignment/coordinateReg/image_infer.py", line 88, in __init__
self.detector.prepare(ctx_id=ctx_id)
AttributeError: 'NoneType' object has no attribute 'prepare'
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I have downloaded the model and put it in the correct link , What is the problem I am facing and what do I need to do to fix it.
thanks.