Get Malformed error while patch request to update payment - python-2.7

Question

I want to reduce some items of my order from payment. That's why I'm using replace method of PayPal python API that allows to update or add data after an object of payment has been created.
Error:
{u'message': u'Incoming JSON request does not map to API request', u'debug_id': u'd57742e9d3b03', u'name': u'MALFORMED_REQUEST', u'information_link': u'https://developer.paypal.com/webapps/developer/docs/api/#MALFORMED_REQUEST'}
Code:
create payment:
I added two products while creating a payment object.
payment = Payment({
"intent": "sale",
"payer": {
"payment_method": "paypal"},
"redirect_urls": {
"return_url": "http://localhost:3000/payment/execute",
"cancel_url": "http://localhost:3000/"},
"transactions": [{
"item_list": {
"items": [{
"name": "Ice-cream",
"sku": "I10001",
"price": "50.00",
"currency": "USD",
"quantity": 12},
{
"name": "Ice-cream12",
"sku": "I100012",
"price": "60.00",
"currency": "USD",
"quantity": 12}
]},
"amount": {
"total": "1320.00",
"currency": "USD"},
"description": "This is the payment transaction description."}]})
payment.create()
Update Payment:
update_payment_json = [
{
"op":"replace",
"path":"/transactions/0/item_list",
"values":{"items":[{
"name": "Ice-cream",
"sku": "I10001",
"price": "50.00",
"currency": "USD",
"quantity": 12,
},]}
},
{
"op":"replace",
"path":"/transactions/0/amount",
"value":
{
"total": "600.00",
"currency": "USD",
"details":{
"subtotal": "600.00",
"shipping":"0.0",
}},
},
]
payment.replace(update_payment_json)

Answer 1

I don't believe the below path is sufficient to determine which item are you updating ? there are 2 items in the item_list correct? if you are updating just 1 of it then you need to qualify it to the right path so that you are clear about which item you are replacing.
"path":"/transactions/0/item_list",