After installing mmdet and mmcv by myself, an error occurs:

ModuleNotFoundError: No module named 'mmcv._ext

This error for mmdet==0.6.0 and mmcv==0.6.2:

ImportError: cannot import name 'deform_conv_cuda'

Enviroment:

• python 3.6
• pytorch 1.10
• cuda 10.2