unmute(events) {
        // Diff array and set to false if we're now empty
        if (isString(events) || isArray(events)) {
            this._muted = difference(this._muted, castArray(events));
            if (!this._muted.length) {
                this._muted = false;
            }
        }
        else {
            this._muted = false;
        }

        return this;
    }
Resume events.

@param {array} events Events to unmute.
@return {Tree} Tree instance.