type: object
required:
  - variant_id
  - quantity
properties:
  variant_id:
    type: string
    description: The id of the Product Variant to generate the Line Item from.
  quantity:
    type: number
    description: The quantity of the Product Variant to add to the Line Item.
  metadata:
    type: object
    description: An optional key-value map with additional details about the Line Item.