{
    "$schema": "http://json-schema.org/draft-04/schema#",
    "type": "object",
    "properties": {
      "approved": {
        "type": "boolean"
      },
      "error": {
        "type": ["string", "null"]
      },
      "itemId": {
        "type": "string"
      },
      "orderId": {
        "type": "string"
      },
      "processedBy": {
        "type": "string"
      },
      "processingTimestamp": {
        "type": "string"
      },
      "quantity": {
        "type": "integer"
      }
    },
    "required": [
      "approved",
      "itemId",
      "orderId",
      "processedBy",
      "processingTimestamp",
      "quantity"
    ]
  }