I've update the code above. The error got away but the response is like:

{
  "results": [
    {
      "facet_counts": [],
      "found": 0,
      "hits": [],
      "out_of": 0,
      "page": 1,
      "request_params": {
        "collection_name": "collection1",
        "per_page": 10,
        "q": "pizza"
      },
      "search_cutoff": false,
      "search_time_ms": 0
    },
    {
      "facet_counts": [],
      "found": 0,
      "hits": [],
      "out_of": 0,
      "page": 1,
      "request_params": {
        "collection_name": "collection2",
        "per_page": 10,
        "q": "pizza"
      },
      "search_cutoff": false,
      "search_time_ms": 0
    }
  ]
}

It's not getting any matches in the response and hence I'm not able to test the build. Please suggest if there's any other update in the code. Thanks!