public function listBox($id)
 {
     $unique = PayrollHeading::distinctDeductions();
     if ($id != '') {
         $unique = array(0);
     }
     $deductions = self::orderBy('desc')->whereNotIn('id', $unique)->get();
     $rows = array('0' => '');
     foreach ($deductions as $deduction) {
         $rows[$deduction->id] = $deduction->desc;
     }
     return $rows;
 }