curl --request GET \
  --url http://127.0.0.1:8080/api/v1/invoices/{invoice_id}/lines

{
  "lines": [
    {
      "id": "3c90c3cc-0d44-4b50-8888-8dd25736052a",
      "description": "<string>",
      "quantity": 123,
      "unit_price": 123,
      "amount": 123,
      "metadata": "<unknown>"
    }
  ]
}