allOf:
  - $ref: "../../../shared/models/form_factor/generated.yml"
  - $ref: "../../../shared/models/form_factor/from.yml"

  - type: object

    required:
      - id
      - from

    properties:
      id:
        $ref: "../attributes/ltr_id.yml"

      template_id:
        allOf:
          - description: The unique ID of the HTML template used for the letter.
          - $ref: "../../../shared/attributes/model_ids/tmpl_id.yml"

      template_version_id:
        allOf:
          - description: The unique ID of the specific version of the HTML template used for the letter.
            type: string
          - $ref: "../../../shared/attributes/model_ids/vrsn_id.yml"

      object:
        type: string
        description: Value is resource type.
        enum:
          - letter
        default: letter