def test_attr_selector_creates_customjs_int(self) -> None:
        m1 = SomeModel()
        m2 = SomeModel()
        assert len(m1.js_property_callbacks) == 0
        m1.js_link('a', m2, 'b', 1)
        assert len(m1.js_property_callbacks) == 1
        assert "change:a" in m1.js_property_callbacks
        cbs = m1.js_property_callbacks["change:a"]
        assert len(cbs) == 1
        cb = cbs[0]
        assert isinstance(cb, CustomJS)
        assert cb.args == dict(other=m2)
        assert cb.code == "other.b = this.a[1]"