Upload file to field using PHP-SDK

Hi all!

Using this documentation I am trying to upload a file to a field in a Leads record, but it doesn't work.

Below is my code:

$record = get_record('Leads', <Lead-ID>);

```
$filepath = '/path/to/my/file.docx';
```
```
$record->uploadAttachment($filepath);
```

Besides not seeing the file appear in the Leads record, I also get an error message:

Notice: Undefined offset: 1 in zcrmsdk\crm\api\response\CommonAPIResponse->setResponseJSON() (line 105 of /var/www/html/vendor/zohocrm/php-sdk/src/crm/api/response/CommonAPIResponse.php).

Could you please post a working example code snippet? And is there any way to specify the field in the Leads record to which the file is uploaded?

Thank you in advance!