CakePHP IN数组条件不能使用一个键

I'm trying to find with the condition that the field type has one of a group of selected values. The problem I'm facing is that when select only one item, like this:

$this->Ads->find('all', array(
    'conditions' => array(
       'type IN' => array('other');
    )
);

CakePHP gives an SQL error:

You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '= ('other')' at line 1

Query looks like: type IN = ('other') which is wrong.

Is this a CakePHP bug or am I doing something wrong?

I am using CakePHP version: 2.4.2

You don't need the IN operator, Cake works out the variable type (array/string) and adds it automatically when needed:

// type = 'other'
'conditions' => array(
    'type' => 'other'
)

// type = 'other' syntax 2
'conditions' => array(
    'type' => array('other'),           
)

// type IN ('other', 'other2', 'other3'):
'conditions' => array(
    'type' => array('other', 'other2', 'other3') 
)