code: def test_roundtrip():
      from pybind11_tests import Pickleable
  
      p = Pickleable("test_value")
      p.setExtra1(15)
      p.setExtra2(48)
  
      data = pickle.dumps(p, 2)  # Must use pickle protocol >= 2
      p2 = pickle.loads(data)
      assert p2.value() == p.value()
      assert p2.extra1() == p.extra1()
      assert p2.extra2() == p.extra2()
  
label_desc: Use image node_id 1 for calling a global function with example usage: test_roundtrip() without return types