curl --request GET \
  --url https://openapi.pluuug.com/v1/settlement/{settlement_id} \
  --header 'X-API-Key: <api-key>' \
  --header 'X-Signature: <api-key>'

{
  "id": 123,
  "title": "<string>",
  "status": "C",
  "amount": 1,
  "additionalAmount": 1,
  "vat": 1,
  "settlementRound": 123,
  "isTaxInvoiceIssued": true,
  "isTaxInvoiceNeeded": true,
  "typeAlias": "<string>",
  "created": "2023-11-07T05:31:56Z",
  "contract": {
    "id": 123,
    "title": "<string>",
    "amount": 123,
    "type": "I",
    "status": "P",
    "startDate": "2023-12-25",
    "endDate": "2023-12-25"
  },
  "type": {
    "id": 123,
    "baseType": "INI",
    "category": "I",
    "title": "<string>",
    "allowsMultipleRounds": true
  },
  "dueDate": "2023-12-25",
  "settledDate": "2023-12-25",
  "taxInvoiceIssuedDate": "2023-12-25",
  "taxInvoiceIssueDueDate": "2023-12-25",
  "inChargeSet": [
    {
      "id": 123,
      "nickname": "<string>",
      "email": "<string>",
      "isActive": true,
      "grade": {
        "id": 123,
        "title": "<string>"
      }
    }
  ]
}