content: {
    "$defs": {
      "Stamp": {
        "description": "Stamp defines an official seal of approval from a third party like a governmental agency or intermediary and should thus be included in any official envelopes.",
        "properties": {
          "prv": {
            "$ref": "https://gobl.org/draft-0/cbc/key",
            "description": "Identity of the agency used to create the stamp usually defined by each region.",
            "title": "Provider"
          },
          "val": {
            "description": "The serialized stamp value generated for or by the external agency",
            "title": "Value",
            "type": "string"
          }
        },
        "required": [
          "prv",
          "val"
        ],
        "type": "object"
      }
    },
    "$id": "https://gobl.org/draft-0/head/stamp",
    "$ref": "#/$defs/Stamp",
    "$schema": "https://json-schema.org/draft/2020-12/schema"
  }