{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "$id": "https://cdn.jsdelivr.net/npm/@pie-element/placement-ordering@15.0.6/dist/schemas/session.schema.json",
  "type": "object",
  "properties": {
    "id": {
      "type": "string",
      "description": "Identifier of the session"
    },
    "element": {
      "type": "string",
      "description": "The element the session belongs to"
    },
    "value": {
      "type": "array",
      "items": {
        "type": [
          "string",
          "null"
        ]
      },
      "description": "The choice ids in the order the learner placed them. With a placement area, an empty target is a hole in the array, which serializes as null."
    }
  },
  "definitions": {}
}