Load checkpoint from Trainer

🤗Transformers
1 
class MyModel(nn.Module):
    def __init__(self, model_args, data_args, training_args, lora_config): 
        super().__init__()
        self.model_args = model_args
        self.data_args = data_args
        self.training_args = training_args
        self.device = training_args.device
        self.llama = LlamaForCausalLM.from_pretrained(\
            model_args.model_name_or_path, \
            cache_dir = model_args.cache_dir, \
        )
        self.llama= get_peft_model(self.llama, lora_config)

This is my model code, I customized it.

model = MyModel(model_args, data_args, training_args, lora_config)

trainer = Seq2SeqTrainer(
        model=model,
        args=training_args,
        train_dataset=train_data,
        eval_dataset=valid_data,
        tokenizer = tokenizer,
        data_collator = data_collator,
        compute_metrics=compute_metrics if training_args.predict_with_generate else None,
    )

During the train, I saved a model every 1000 steps.
And I’d like to evaluate this 1000 steps after training by loading checkpoint.

In this case,
model = AutoModel.from_pretrained(“checkpoint_dir”) causes an error and says that there is no config.json.

In the example code at Huggingface transformers, to begin with, the model is defined Huggingface model like GPT2LMHeadModel, which allows model = GPT2LMHeadModel.from_pretrained(“checkpoint_dir”) to work.
This is a different situation from mine(custom model)

How can I load the saved checkpoint model which was defined as a custom model, with Huggingface Trainer to evaluate this model?