How can I access nested data?

Question

Im currently using Drupal's http client manager module to pull data from a json endpoint. I am having trouble getting this to work for a nested structure like this.

{
  count: 2431
  page_info: []
  content:
    0:
      id: 1
      title: "Ipsum lorem"
    1:
      id: 2
      title: "dolor set"
}

The service description looks like this.

operations:
  GetEvents:
    httpMethod: "GET"
    uri: "8892e8de"
    summary: "Gets the available Posts."
    responseClass: "PostsList"

models:
  Posts:
    type: "object"
    location: "json"
    properties:
      content:
        location: "json"
        type: "array"

  PostsList:
    type: "array"
    location: "json"
    items:
      "$ref": "Posts"

This is returning an empty object of arrays and not picking up any data.

How can I access the nested data?