How to attach document(s) to Purchase Order via API?

How to attach document(s) to Purchase Order via API?

Is it possible to attach a PDF/document (say of a signed document) to a Purchase Order using the API, Deluge or any other method programmatically?

For example: In the code snippet below, the purchase order has a documents array. How can the zoho inventory API or Deluge invokeurl task update this?

  1. {
		"purchaseorder_id": 2498380000023020596,
		"branch_id": 2498380000002075005,
		"branch_name": "Head Office",
		"documents": [
			
		],
		"contact_category": "",
		"purchaseorder_number": "PO-01142",
    ...
    }