curl --request POST \
  --url https://rest.staging.nickel.com/bill/pay \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "payments": [
    {
      "billId": "<string>",
      "merchantPaymentMethodId": "<string>",
      "vendorPayoutMethodId": "<string>",
      "notificationEmails": [
        "<string>"
      ],
      "vendorId": "<string>",
      "withdrawalDateEpochMillis": 123,
      "vendorMemo": "<string>"
    }
  ],
  "idempotencyKey": "<string>"
}
'

{
  "billPayments": [
    {
      "id": "<string>",
      "status": "<string>",
      "amountInCents": 123,
      "createdAt": 123,
      "vendorPayoutMethodId": "<string>",
      "billPayableId": "<string>"
    }
  ],
  "billErrors": [
    {
      "billId": "<string>",
      "error": "<string>"
    }
  ]
}