Defining an exception class and calling def(...), def_property(...), etc.

[mdorier]

I am trying to make a C++ exception class available in python. This class has some member variables and member functions that I would like to also make available in Python. The pybind11::register_exception<T> function returns a pybind11::exception<T>, which doesn't have def(...), def_property(...), etc.
How do I do such a definition?

I tried the following:

py11::class_<pymargo_exception>(m, "MargoException")
        .def_readonly("code", &pymargo_exception::code);
    py11::register_exception<pymargo_exception>(m, "MargoException");

But I'm getting an error at runtime: ImportError: Error during initialization: multiple incompatible definitions with name "MargoException".