function getQuantity(){
if($this->task_activity_id > 0){
$ta = new SI_TaskActivity();
if($ta->get($this->task_activity_id) === FALSE){
$this->error = 'SI_InvoiceLineLink::getQuantity(): Error getting task activity: '.$ta->getLastError();
return FALSE;
}
return $ta->getQuantity();
}elseif($this->expense_id > 0){
return 1.0;
}elseif($this->payment_schedule_id > 0){
return 1.0;
}
return 'Unknown';
}