Trouble with flash function on timeline

Hi all, i trying reuse a function many times so i decide to put it inside the timeline and whenever the movieclip move it will call the function, but it dont work. -_-

timeline code
function moveapple(){
this._y += 5;
}

movieclip code
onClipEvent(enterFrame){
moveapple();
}

but the movie clip dont move -_-

thxs for reading