gemma-3-4b-it failed on 'Gemma3TextModel' object has no attribute 'model'

[yuki-97]

gemma-3-4b-it will fail on AttributeError: 'Gemma3TextModel' object has no attribute 'model' on transformers==4.52.3

Need to adapt to transformers==4.52.3.

[mrm-196]

I'm also consistently running into this issue when trying to DPO-tune Gemma3 4B model. Sample command:

uv run ./examples/run_dpo.py \
  --config ./examples/configs/dpo.yaml \
  cluster.num_nodes=1 \
  cluster.gpus_per_node=8 \
  policy.model_name="google/gemma-3-4b-it" \
  policy.tokenizer.name="google/gemma-3-4b-it" \
  policy.train_micro_batch_size=1 \
  policy.train_global_batch_size=128 \
  policy.max_total_sequence_length=2048 \
  dpo.max_num_steps=10 \
  dpo.val_at_start=false \
  dpo.val_period=-1 \
  logger.wandb_enabled=True \
  logger.wandb.name="sample-job-name"