What's the detail implement in CustomLayerDecayOptimizerConstructor?

Hi, I currently migrate the InternImage into mmdetection==2.28.1, and I encounter the error that say the CustomLayerDecayOptimizerConstructor is not implemented. But I didn't find the impelment of CustomLayerDecayOptimizerConstructor in the mmdet.core.optimizers or somewhere else. I wonder where can I found this file? Thanks for anyone's reply.

Oh, I found it. It is in Internimage/detection/mmcv_custom