code: def save_low_bit(self, *args, **kwargs):
      invalidInputError(
          self.config.to_dict().get(
              "bigdl_transformers_low_bit", False
          ),
          f"Detected this model is not a low-bit model, please use from_pretrained's"
          f" load_in_4bit or load_in_low_bit parameter to load a 4-bit model first.",
      )
      if hasattr(self.config, "quantization_config"):
          delattr(self.config, "quantization_config")
          delattr(self.config, "_pre_quantization_dtype")
  
      self.to("cpu")
  
      kwargs["safe_serialization"] = False
  
      architectures = getattr(self.config, "architectures", None)
      model_type = getattr(self.config, "model_type", None)
      self.save_pretrained(*args, **kwargs)
  
      if architectures:
          self.config.update({"architectures": architectures})
      if model_type:
          self.config.update({"model_type": model_type})
  
      self.config.save_pretrained(args[0])
      if self.can_generate():
          self.generation_config.save_pretrained(args[0])
  
      import json
      import os
  
      # We conveniently save all the keys of the model to have them on hand,
      # so that when using 'low_cpumem load',
      # it's not necessary to load the entire model to extract its keys
      # and we can avoid gc not triggered potentially.
      load_keys = {
          "all_checkpoint_keys": list(self.state_dict().keys())
      }
      with open(
          os.path.join(args[0], "load_keys.json"), "w"
      ) as json_file:
          json.dump(load_keys, json_file)
  
imports: import transformers
  from transformers.configuration_utils import PretrainedConfig
  from .utils import extract_local_archive_file, load_state_dict, get_local_shard_files
  from bigdl.llm.ggml.quantize import ggml_tensor_qtype
  from bigdl.llm.utils.common import invalidInputError
  from bigdl.llm.transformers.gguf.api import load_gguf_model
  import torch
  import warnings
  import copy
  from .utils import logger
label_desc: Use image node_id 1 for calling a global function with example usage: save_low_bit() without return types