generic type param missing from signature

[alexeagle]

* @param {function(this:SCOPE)|{handleEvent:function()}|null} listener Function
 *     or object that has a handleEvent method.
 * @param {number=} opt_delay Milliseconds to wait; default is 0.
 * @param {SCOPE=} opt_handler Object in whose scope to call the listener.
 * @return {number} A handle to the timer ID.
 * @template SCOPE
 */
goog.Timer.callOnce = function(listener, opt_delay, opt_handler) {

static callOnce < SCOPE > (listener : ( ( ) => any | { handleEvent : ( ) => any } ) , opt_delay ? : number , opt_handler ? : ( ) ) : number ;

the type of opt_handler is ( ) which is not valid