Solved by ptrblck in post #3 
              
              
                load_state_dict is a method, which should get the state_dict as its input. 
Currently you are reassigning the state_dict to the function: 
self.model.load_state_dict = checkpoint['state_dict']
self.optimizer.load_state_dict = checkpoint['optimizer']

Replace these lines of code with: 
self.model.loa…