{
    "$schema": "http://json-schema.org/draft-07/schema#",
    "definitions": {
        "foo.Date": {
            "properties": {
                "day": {
                    "type": "number"
                },
                "month": {
                    "type": "number"
                },
                "year": {
                    "type": "number"
                }
            },
            "type": "object"
        }
    },
    "properties": {
        "date": {
            "$ref": "#/definitions/foo.Date"
        }
    },
    "required": [
        "date"
    ],
    "type": "object"
}