Checkpoint error in AGEM

[TomokazuNakamura]

An error occurs when saving "checkpoint.pkl" only when strategy=AGEM.

cl_strategy = avalanche.training.AGEM(
model, optimizer, criterion, train_mb_size=config.batch_size, train_epochs=config.epochs,
eval_mb_size=config.batch_size, device=device, evaluator=evaluator,
patterns_per_exp=int(args.parameter1), eval_every=1)
save_checkpoint(cl_strategy, fname) #"fname" is name of the checkpoint file