$/**$

Accessor method to get the current element of this sequence.

Eparam $-$ none

@precondition

isCurrent$()$ returns true.

@return

the current element of this sequence, possibly null

@exception IllegalStateException

Indicates that there is no current element, so

getCurrent may not be called.

$**$

public Ball getCurrent$()$

$\{$

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

$//$ TODO: Implement this code.

$\}$

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