{
    "type": "object",
    "properties": {
        "direction": {
            "$ref": "#/definitions/Cardinal"
        }
    },
    "required": [
        "direction"
    ],
    "definitions": {
        "Cardinal": {
            "enum": [
                "east",
                "north",
                "south",
                "west"
            ],
            "type": "string"
        }
    },
    "$schema": "http://json-schema.org/draft-04/schema#"
}