// Inserts the specified element at the specified position in this list.

// Shifts the element currently at that position (if any) and any subsequent

// elements to the right (adds one to their indices).

// if(index < 0 or index > this.size), throws IndexOutOfBoundsException.

// E.g, if this list is [dummy]->["A"]->["B"]->["C"] with size = 3.

// add(0,D) will result in [dummy]->["D"]->["A"]->["B"]->["C"].

// Continuing on the previous add() call, add(1,"E") will

// change the existing list to [dummy]->["D"]->["E"]->["A"]->["B"]->["C"].

public void add(int index, Object o) {

//code here

}