How to make a stick man running when pressing a key?

I created a movieclip named stickman. In that, I created an animation by drawing a sequence of move in everyframe, so that stickman can run. Now what I want is that when I press a key, the stick man will run from left to right and when I release the key, it will stop. This is my code:

RunningMan.stop();

stage.addEventListener(KeyboardEvent.KEY_DOWN,keypresseddown);
function keypresseddown(event:KeyboardEvent😞void
{

var key:uint = event.keyCode;
switch (key) {
   case Keyboard.LEFT :
   {
       RunningMan.play();
       RunningMan.x-=10;
       RunningMan.scaleX=-1;
      
   };
    case Keyboard.RIGHT :
    {
        RunningMan.play();  //play animated run
        RunningMan.x+=10;
        RunningMan.scaleX=1;
       
    };
    default: RunningMan.stop();
   }
}

However, when I pressed and held a key, it moved from left to right without animated run.

How can I fix it? Thanks in advance.