what is blank $1$

public double middleTotal

$($DoublyLinkedList sList, double low, double high$)$

$\{$

double sum $=0$;

while$($sList$.$hasMoreElements$())\{$

int nextElement $=($Integer$)$sList$.$nextElement$()$;

$\_\_\_\_\_\_\_\_\_\_\_\_\_\_(1)\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_$;

$\}$

return sum;

$\}$