$/**$

The first element $($if any$)$ of this sequence is now current.

@param $-$ none

@postcondition

The front element of this sequence $($if any$)$ is now the current element $($but

if this sequence has no elements at all, then there is no current

element$)$

$**/$

public void start$()$

$\{$

assert wellformed$()$ : "invariant failed at start of start";

$//$ TODO: Implement this code.

assert wellFormed$()$ : "invariant failed at end of start";

$\}$

Can anyone help me to complete todo