add download_model.py

Author: edgchen1

mobile/examples/model_tester/ios/ModelTester/model/download_model.py

@@ -0,0 +1,11 @@
+from pathlib import Path
+from onnx import hub
+import onnx
+
+if __name__ == "__main__":
+    script_dir = Path(__file__).parent
+    output_path = script_dir / "model.onnx"
+    model_name = "MobileNet v2-1.0-fp32"
+    
+    model = hub.load(model_name)
+    onnx.save(model, output_path)

mobile/examples/model_tester/ios/ModelTester/model/download_model.requirements.txt

@@ -0,0 +1 @@
+onnx

mobile/examples/model_tester/ios/ModelTester/model/readme.md

@@ -1 +1,10 @@
 Add a model here and name it model.onnx.
+
+You can run `download_model.py` to obtain a model.
+
+```bash
+python -m pip install -r ./download_model.requirements.txt
+
+python ./download_model.py
+```
+