code: def test_return_defaults():
      response = client.get("/")
      assert response.json() == {"sub": {}}
  
imports: from typing import Optional
  from fastapi import FastAPI
  from fastapi.testclient import TestClient
  from pydantic import BaseModel
label_desc: Use image node_id 6 for calling a global function with example usage: test_return_defaults() without return types