I have to send this data threw curl:

```
-d '{"payer": {
        "default_payment_instrument":"BANK_ACCOUNT",
        "allowed_payment_instruments":["BANK_ACCOUNT"],
        "default_swift":"FIOBCZPP",
        "contact":{"first_name":"First",
                   "last_name":"Last",
                   "email":"first.last@example.com"
        }
    },
}'

```

How am I supposed to save those data into `fields` variable?

```
$fields = {
  "payer": {
        "default_payment_instrument":"BANK_ACCOUNT",
        "allowed_payment_instruments":["BANK_ACCOUNT"],
        "default_swift":"FIOBCZPP",
        "contact":{"first_name":"First",
                   "last_name":"Last",
                   "email":"first.last@example.com"
        }
    },
};
$field_string = http_build_query($fields);
curl_setopt($process, CURLOPT_POSTFIELDS, $field_string);

```