add py to onnx tool

tools/pt2onnx.py

@@ -0,0 +1,23 @@
+import argparse
+
+from ultralytics import YOLO
+
+
+def main(checkpoint_path):
+    model = YOLO(checkpoint_path)
+    model.export(
+        format="onnx",
+        imgsz=(640, 480),
+        dynamic=True,
+        simplify=True,
+        half=True,
+        workspace=0.8,
+        batch=1,
+        device="cpu"
+    )
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument("checkpoint_path", type=str)
+    args = parser.parse_args()
+    main(args.checkpoint_path)