{
    "event": "Wrong variation field type",
    "mainVariation": [
        "e4",
        "e5",
        "Nf3",
        "Nc6",
        {
            "notation": "Bb5",
            "variations": [
                [ "Bc4" ],
                [ "Nc3" ],
                "not-a-variation"
            ]
        }
    ]
}