code: def test_bind_protected_functions():
      """Expose protected member functions to Python using a helper class"""
      a = m.ProtectedA()
      assert a.foo() == 42
  
      b = m.ProtectedB()
      assert b.foo() == 42
      assert m.read_foo(b.void_foo()) == 42
      assert m.pointers_equal(b.get_self(), b)
  
      class C(m.ProtectedB):
          def __init__(self):
              m.ProtectedB.__init__(self)
  
          def foo(self):
              return 0
  
      c = C()
      assert c.foo() == 0
  
imports: import pytest
  import env
  from pybind11_tests import ConstructorStats, UserType
  from pybind11_tests import class_
label_desc: Use image node_id 20 for calling a global function with example usage: test_bind_protected_functions() and returns: int