How to mock `sorting` in jointjs `new dia.Paper()`

I tried to mock jointjs, which I’m using like this:

const Canvas = () => {
  const g = new dia.Graph({}, { cellNamespace: shapes })
  const graph = useRef(g)
  const paperEl = useRef(null)

  useEffect(() => {
    const paper = new dia.Paper({
      el: paperEl.current,
      model: graph.current,
      cellViewNamespace: shapes,
      interactive: false,
      width: '100%',
      height: 800,
      async: true,
      sorting: dia.Paper.sorting.APPROX // how do I have to mock this?
    })

    return () => {
      paper.removeTools()
    }
  }, [])

  return (
    <Box
      className="paper"
      id="paper"
      ref={paperEl}
    />
  )
}

But with this mock I do get the error TypeError: Cannot read properties of undefined (reading 'APPROX')

jest.mock('jointjs', () => {
  return {
    dia: {
      Graph: jest.fn(),
      Paper: jest.fn().mockImplementation(() => ({
        model: jest.fn(),
        sorting: { APPROX: 'sorting-approximate' }, // <-- this doesn't work
        removeTools: jest.fn()
      }))
    }
  }
})