{
    "facets": [ 
        {
            "field": "subject",
            "terms": { 
            }
        },
        {
            "field": "creator",
            "terms": { 
            }
        },
        {
            "field": "format",
            "terms": { 
                "audio/wav": 1,
                "image/heic": 1
            }
        }
        
    ]
}