Function newfunc 

pub unsafe extern "C" fn newfunc<Meth: MethodDef<Func>>(
    subtype: *mut PyTypeObject,
    args: *mut PyObject,
    kwargs: *mut PyObject,
) -> *mut PyObject

External symbol called by Python, which calls the provided Rust function.

The Rust function is supplied via the generic parameter Meth.

Safety

The interpreter must be attached