cakephp模型中的其他方法导致500错误

function getID($id) {
 $tmp = $this->find(\"all\",array(\'conditions\'=>array(\'Model.id\'=>$id)));
 return $tmp;
}

function getTotalQuestions(){
 $tmp=$this->Model->getID(7);
 debug($tmp);
}

function get_id($id = null) {
   // code here
}

function get_total_questions() {
   $tmp = $this->Model->get_id(7);
  // ...
}