Problems when i use pretrainde model to fine-tune my model

Refer to https://github.com/PPPW/deep-learning-random-explore/blob/master/CNN_archs/cnn_archs_more.ipynb
I have make a new model.The same time,i want to change AdaptiveConcatPool2d layer to SPP_net layer.i have change the code in local code in my PC,but it don’t work ,just like i haven’t change the code.
By the way,SSP_net is a layer i add in the code.

Anyone help me?