Kohana 3 throwing a fatal error when validating

Trying to follow the example on the wiki here: extending model Auth user class, and I am hitting a fatal error when it goes to validate.

ErrorException [ Fatal Error ]: Class 'Validate' not found

Any ideas? Here's the piece of code it fails on:

class Model_User extends Model_Auth_User
  {
    public function validate_create(& $array) 
    {
       开发者_运维问答 // Initialise the validation library and setup some rules       
        $array = Validate::factory($array)
                        ->rules('password', $this->_rules['password'])
                        ->rules('username', $this->_rules['username'])
                        ->rules('email', $this->_rules['email'])
                        ->rules('password_confirm', $this->_rules['password_confirm'])
                        ->filter('username', 'trim')

Using 3.1? Validate is now Validation and filters have been removed.

Check out http://kohanaframework.org/3.1/guide/kohana/upgrading and http://forum.kohanaframework.org/discussion/comment/57374.