Adding wrapper code for already wrapped types

[muffgaga]

struct GENPYBIND(visible) TopLevel
{
    // already wrapped somewhere else
    typedef SomeComponents some_type GENPYBIND(opaque);

    GENPYBIND_MANUAL({
        auto ism = parent->py::is_method(attr);
        auto attr = parent.attr("some_type");
        attr.attr("to_numpy") = parent->py::cpp_function(/* code */, ism);
    })
};

In some cases it might be nice to modify the wrapper code of some element contained in the wrapper code of a TopLevel class instead of adding the member dynamically via attr.