Execution order of multiple validation rules

Below is a typical validations rules for User Model. The validations rules of a field are ran from bottom up. In this case, for the email field, it will run stringLength, email and then isUnique rules.

<?php
class User extends AppModel
{
  var $name = "User";
 
  // Validation rules.
  var $validate = array(
    'username'=>array(
        'isUnique'=>array(
            'rule'=>'isUnique',
            'message'=>'This username has already been taken.',
            ),
        'stringLength'=>array(
            'rule'=>array('between', 1, 40),
            'message'=>'This field must be between 1 and 40 characters long.',
            ),
        ),
 
    'password'=>array(
        'stringLength'=>array(
            'rule'=>array('between', 6, 40),
            'message'=>'This field must be between 6 and 40 characters long.',
            ),
        ),
 
    'email'=>array(
        'isUnique'=>array(
            'rule'=>'isUnique',
            'message'=>'This email already existed.',
            ),
        'email'=>array(
            'rule'=>array('email', true),
            'message'=>'Please supply a valid email address.',
            ),
        'stringLength'=>array(
            'rule'=>array('between', 1, 40),
            'message'=>'This field must be between 1 and 40 characters long.',
            ),
        ),
    );    
}
?>