Ticket Attachment using private app

Can i add a ticket attachment using my private app just like i add comment using zaf client

client.invoke('ticket.comment.appendText', testText)

Is there a property in ticket node that allows me to add a attachment to the ticket without sending an actual reply e.g. 

client.invoke('ticket.comment.addAttachment', [{contentUrl: "https://_subdomain_/attachments/token/TOKEN/?name=order_issue.pdf",contentType: 'application/pdf',