extensions/sample/x-sampletwo.json

        {
            "definitions": {
                "Book": {
                    "type": "object",
                    "id": "x-sampletwo-book",
                    "required": [
                        "code",
                        "message"
                    ],
                    "properties": {
                        "code": {
                            "type": "integer",
                            "format": "int32"
                        },
                        "message": {
                            "type": "integer"
                        }
                    }
                },
                "Shelf": {
                    "type": "object",
                    "id": "x-sampletwo-shelf",
                    "required": [
                        "foo1",
                        "bar"
                    ],
                    "properties": {
                        "foo1": {
                            "type": "integer",
                            "format": "int32"
                        },
                        "bar": {
                            "type": "integer"
                        }
                    }
                }
            }
        }