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

[slw123]

hello! when i run code "python '/home/slw/Downloads/autoRIFT/testautoRIFT.py' -m "/mnt/hgfs/E/lidar/ali/lco8/of_st/clip/19911213_clip.tif" -s "/mnt/hgfs/E/lidar/ali/lco8/of_st/clip/19921113_clip.tif" -fo 1" throw the error, like picture. how can i to resolve this error? thank you very much!