def test_no_cpython_wrapper(self):
        """
        Test overloading whose return value cannot be represented in CPython.
        """
        # Test passing Module type from a @overload implementation to ensure
        # that the *no_cpython_wrapper* flag works
        ok_cfunc = jit(nopython=True)(non_boxable_ok_usecase)
        n = 10
        got = ok_cfunc(n)
        expect = non_boxable_ok_usecase(n)
        np.testing.assert_equal(expect, got)
        # Verify that the Module type cannot be returned to CPython
        bad_cfunc = jit(nopython=True)(non_boxable_bad_usecase)
        with self.assertRaises(TypeError) as raises:
            bad_cfunc()
        errmsg = str(raises.exception)
        expectmsg = "cannot convert native Module"
        self.assertIn(expectmsg, errmsg)

        Test overloading whose return value cannot be represented in CPython.
        
numba/tests/test_extending.py