code: def test_stl_ownership():
      cstats = ConstructorStats.get(m.Placeholder)
      assert cstats.alive() == 0
      r = m.test_stl_ownership()
      assert len(r) == 1
      del r
      assert cstats.alive() == 0
  
imports: import pytest
  from pybind11_tests import ConstructorStats, UserType
  from pybind11_tests import stl
label_desc: Use image node_id 20 for calling a global function with example usage: test_stl_ownership() without return types