[BUG] `load_model_trainer_states_from_checkpoint()` function is broken

[Legoclones]

Bug description

The transformers4rec.torch.trainer.load_model_trainer_states_from_checkpoint() function can only load t4rec_model_class.pkl, all the other loads are broken. The utils.serialization.load() function is called 4 times in the function, but only one of them successfully loads, the other throw errors. I believe this is because load() is expecting an _io.BufferedReader object (resulting from open()) instead of a path.

Correctly implemented:

Transformers4Rec/transformers4rec/torch/trainer.py

Lines 744 to 746 in 5d59d14

	model = load(
	open(os.path.join(checkpoint_path, "t4rec_model_class.pkl"), "rb")
	)

Incorrectly implemented:

Transformers4Rec/transformers4rec/torch/trainer.py

Line 753 in 5d59d14

load(os.path.join(checkpoint_path, "pytorch_model.bin"), torch_load=True)

Transformers4Rec/transformers4rec/torch/trainer.py

Line 757 in 5d59d14

checkpoint_rng_state = load(rng_file, torch_load=True)

Transformers4Rec/transformers4rec/torch/trainer.py

Line 766 in 5d59d14

load(os.path.join(checkpoint_path, "scaler.pt"), torch_load=True)

Steps/Code to reproduce bug

Run the following code with a Model checkpoint at /checkpoint:

from transformers4rec import torch as tr

trainer = tr.trainer.Trainer(model=tr.model.base.Model(), args=None)
trainer.load_model_trainer_states_from_checkpoint('/checkpoint')

Expected behavior

The function call shouldn't be erroring.

Environment details

• Transformers4Rec version: 23.12.0
• Platform: Linux
• Python version: 3.10.12
• Huggingface Transformers version: 4.27.1
• PyTorch version (GPU?): 2.1.2 (no)