void addFirst(Object element)
// Inserts the given element at the beginning of this list.
void addLast(Object element)
// Appends the given element to the end of this list.
Object getFirst()
// Returns the first element in this list
Object getLast()
// Returns the last element in this list
Object removeFirst()
// Removes and returns the first element from this list
Object removeLast()
// Removes and returns the last element from this list