def test_unregister(self):
        def func():
            pass

        # register new callback
        myhook = TemplateHook()
        myhook.register(func)
        self.assertListEqual(myhook._registry, [func, ])

        # unregister callback
        myhook.unregister(func)
        self.assertListEqual(myhook._registry, [])

        # try to unregister twice should do nothing
        myhook.unregister(func)
        self.assertListEqual(myhook._registry, [])
    def test_unregister(self):
        def func():
            pass

        # register new callback
        myhook = TemplateHook()
        myhook.register(func)
        self.assertListEqual(myhook._registry, [
            func,
        ])

        # unregister callback
        myhook.unregister(func)
        self.assertListEqual(myhook._registry, [])

        # try to unregister twice should do nothing
        myhook.unregister(func)
        self.assertListEqual(myhook._registry, [])