What precedence for 'format' is while content negotiation?

Reading the [page](http://www.django-rest-framework.org/api-guide/content-negotiation/) There are three variants of format selection: curl -uadmin:admin "http://localhost:8080/alfresco/service/hellouser.json; curl -uadmin:admin

Validation Error with infos about the positions in a list

Hello, we are having a form with a list of steps.. When sending those, we would like to know, *which one had Validation errors *to mark the input field as invalid. How can this be done? *This is the POST, sending a list of 3 Steps* "steps": [ {