public function loadDebtors(array $debtors)
 {
     if (!$this->validateDebtors($debtors)) {
         return false;
     }
     $this->clearDebtors();
     foreach ($debtors as $arr) {
         $customer = Model_Customer::find_by_custid($arr[0]);
         if (!is_null($customer)) {
             $this->Debtors[$customer->custid] = array('customer' => $customer, 'amount' => $arr[1]);
         }
     }
     $this->save();
     return $this;
 }