Accessing nested functions and scope?

Okay, this would make my life a lot easier if this could be done somehow.
How can one class access a nested function in another class.
Examplish.


main class{
   public function main(){
      doSomethin();
   public function doSomethin(){
              secondFile.dostuff();
          function doSomethin2(){ //  <----Nested Function
             

        }
      }
   }
}
//In a separate file
public function dostuff(){
     // <====== needs to call doSomethin2() from here somehow when it finished its dostuff!

}
public function


Also, thanks for putting up with my bombardment of stupid.