when i init iscroll in v5.2.0, it can't bind mousewheel event?

[xzjcool]

Code: this.yearScroll = new iScroll('#date-year', {

         mouseWheel: true, tap:true
     });

V5.1.2:

IScroll.prototype = { version: '5.1.2',

_init: function () {
    this._initEvents();

    if ( this.options.scrollbars || this.options.indicators ) {
        this._initIndicators();
    }

    if ( this.options.mouseWheel ) {
        this._initWheel();
    }

    if ( this.options.snap ) {
        this._initSnap();
    }

    if ( this.options.keyBindings ) {
        this._initKeys();
    }

V5.2.0:

version: '5.2.0',

_init: function () {
    this._initEvents();

// INSERT POINT: _init

}

Any other changes for init?