从类中调用函数

package asas
{           
  public class main extends EventDispatcher
  {
    private static  var instance:main =new main;

    // This method returns the instance of the class.
    public static function get instance() : main {
      if(_instance == null){
        _instance = new main();            
      }
      return _instance;
    }

    public function doCheck():void {
    }
package asas
{           
  public class main e