{
    "index":{
        "analysis":{
            "filter":{
                "my_keep_filter":{
                    "type":"keep",
                    "keep_words" : ["Hello", "worlD"],
                    "keep_words_case" : true
                },
                "my_case_sensitive_keep_filter":{
                    "type":"keep",
                    "keep_words" : ["Hello", "worlD"]
                }
            }
        }
    }
}