TypeError: 'NoneType' object has no attribute '__getitem__'

[alexshaodong]

Traceback (most recent call last): File "run.py", line 199, in train_wrapper(model) File "run.py", line 129, in train_wrapper trainer.train(model, ims, real_input_flag, args, itr) File "/home/dongwei/Desktop/transferable-memory-master/core/trainer.py", line 12, in train cost = model.train(ims, real_input_flag, itr) File "/home/dongwei/Desktop/transferable-memory-master/core/models/model_factory.py", line 52, in train next_frames, _ = self.network(frames_tensor, mask_tensor) File "/home/dongwei/.local/lib/python2.7/site-packages/torch/nn/modules/module.py", line 493, in call result = self.forward(*input, **kwargs) File "/home/dongwei/Desktop/transferable-memory-master/core/models/adaptive_model.py", line 78, in forward l2_loss += self.mse_criterion(c_s_1, c_teacher1[t]) + self.mse_criterion(c_s_2, c_teacher2[t]) TypeError: 'NoneType' object has no attribute 'getitem'