code: def download_yolov8n_onnx_model(
      destination_path: Optional[str] = None,
      image_size: Optional[int] = 640,
  ):
      if destination_path is None:
          destination_path = (
              Yolov8ONNXTestConstants.YOLOV8N_ONNX_MODEL_PATH
          )
  
      destination_path = Path(destination_path)
      model_path = destination_path.parent / (
          destination_path.stem + ".pt"
      )
      download_yolov8n_model(model_path)
  
      from ultralytics import YOLO
  
      model = YOLO(model_path)
      model.export(format="onnx")
  
file_path: sahi/sahi/utils/yolov8onnx.py
imports: from pathlib import Path
  from typing import Optional
  import numpy
  from sahi.utils.yolov8 import download_yolov8n_model
label_desc: Use image node_id 1 for calling a global function with example usage: download_yolov8n_onnx_model(destination_path, image_size) without return types