public function clearDebtors()
 {
     // exclusion
     if ($recovery = Model_Debt_Recovery::find_by_id($this->DebtRecoveryId)) {
         foreach (Model_Debt_Recovery_Run::find_all_by_debt_recovery_id($recovery->id) as $run) {
             // find message count
             if (Model_Message_Log::count(array('conditions' => array('debt_recovery_id = ?', $run->id)) == 0)) {
                 $run->delete();
             }
         }
     }
     $this->Debtors = array();
     return $this;
 }