Classes - my seem like a basic question

1

I have images that I want to appear on the screen using the same animation. It seems logical to use a class and reuse it. I need to know how to trigger my functions within my class. Not my constructior (this will be blank) but one or more of my methods.
The class is very simple how do I call fadeit() from the main timeline?

package{

import flash.display.MovieClip;
import flash.display.*;
import flash.events.*;
import flash.display.Stage;



public class mainImage extends MovieClip {
    

public function mainImage() {

    
}
    
    
    public function fadeit() {
 
    //code to fade it in
}
    
    
}

}