import.json

                    "shelf": 4,
                    "place": 1
                }
            }
        },
        {
            "association": "library.book_position",
            "instance": "$p46",
            "properties": {
                "books": { "id": "$b46"},
                "shelving": { "id": "$s2"},
                "position": {
                    "shelf": 4,
                    "place": 2
                }
            }
        }
    ]
}