code: def test_variant_monostate(doc):
      assert m.load_monostate_variant(None) == "std::monostate"
      assert m.load_monostate_variant(1) == "int"
      assert m.load_monostate_variant("1") == "std::string"
  
      assert m.cast_monostate_variant() == (None, 5, "Hello")
  
      assert (
          doc(m.load_monostate_variant)
          == "load_monostate_variant(arg0: Union[None, int, str]) -> str"
      )
  
imports: import pytest
  from pybind11_tests import ConstructorStats, UserType
  from pybind11_tests import stl
label_desc: Use image node_id 15 for calling a global function with example usage: test_variant_monostate(doc) without return types