getAllAnchors(json) {
        const anchors = [];
        if (json === null) {
            return anchors;
        }

        const findAnchors = function (obj) { //recursion!
            for (const value of Object.values(obj)) {
                if (value instanceof HassAnchor) {
                    anchors.push(value);
                } else if (value instanceof Object) {
                    findAnchors(value);
                }
            }
        };
        findAnchors(json);

        return anchors;
    }
@private
@param {object|null} json
@return {Array<HassAnchor>}