* The `PyO3::ffi` bindings for the C `PyObject` struct no longer derive from
  `Copy` and `Clone`. If you use the ffi directly you will need to remove `Copy`
  and `Clone` from any derived types. Any cases where a PyObject struct was
  copied or cloned directly likely indicates a bug, it is not safe to allocate
  PyObject structs outside of the Python runtime.
