Zoho Desk Attachment

I have a form in Creator that collects information and creates a ticket in Desk. I would also like to attach a file to the ticket using the File Upload form input, but I am not finding much information on how to make that API call. My code for the Create Ticket Attachment call is:

attachmentInfo = Map();

attachmentInfo.put("file",input.File_upload);

response = invokeurl

[

url :"https://desk.zoho.com/api/v1/tickets/" + ticketId + "/attachments"

type :POST

parameters:attachmentInfo

headers:{"orgId":#########}

connection:"zoho_desk_tickets"

];

The result

{"errorCode":"UNPROCESSABLE_ENTITY","message":"Extra query parameter 'file' is present in the input."}