How to install SpinePlugin with other two methods?

Phaser 3
1

** First methods**

this.load.plugin(
    /*key: */ 'SpinePlugin', 
    /*url: */ './plugins/SpinePlugin.js', 
    /*start: */ true, 
    /*mapping: */ 'spine'
);
this.load.setPath('assets/demo/spine');
this.load.spine('boy', 'spineboy-pro.json', 'spineboy-pro.atlas', true);

this method throws error: Uncaught TypeError: this.load.spine is not a function

** Second methods**

scene: {
    preload: preload,
    create: create,
    pack: {
        files: [
            { type: 'scenePlugin', key: 'SpinePlugin', url: 'plugins/SpinePlugin.js', sceneKey: 'spine' }
        ]
    }
}

this method throws error too: Uncaught TypeError: this.load.spine is not a function.

While this one works well.

plugins: {
    scene: [
        { key: 'SpinePlugin', plugin: window.SpinePlugin, mapping: 'spine' }
    ]
}

My Phaser version is 3.22.0.
Should I give some file loader event listen, then use this.load.spine after the event emits?