Fatal error: Call to undefined function validation_errors() à l'aide de codeIgniter

Fatal error: Call to undefined function validation_errors() à l'aide de codeIgniter
voici mon comments.php vue

        <?php echo validation_errors(); ?>

        <?php echo form_open('news/comments'); ?>

            Name   <input type="text" name="comment_name"></input><br />
            Email  <input type="text" name="comment_email"></input><br />
            Comment<input type="text" name="comment_body"></input><br />
            <input type="submit" name="submit" value="Comment it" ></input>

        </form>

voici mon news_model.php

<?php
class News_model extends CI_Model {

public function __construct()
{
    $this->load->database();
}



//set comment

public function set_comment()
{
$this->load->helper('url');
$this->load->helper('date');

$data_c = array(
    'comment_name' => $this->input->post('comment_name'),
    'comment_email' => $this->input->post('comment_email'),
    'comment_body' => $this->input->post('comment_body'),   
);

    return $this->db->insert('comments', $data_c);
}

}

ici mon contrôleur news.php

<?php
class News extends CI_Controller {

public function __construct()
{
    parent::__construct();
    $this->load->model('news_model');


}



public function create_comment()
{
$this->load->helper('form');
$this->load->library('form_validation');


$this->form_validation->set_rules('comment_name', 'comment_name', 'required');
$this->form_validation->set_rules('comment_email', 'comment_email', 'required');
$this->form_validation->set_rules('comment_body', 'comment_body', 'required');

if ($this->form_validation->run() === FALSE)
{
    echo 'failed'; //just for debugging

}
else
{
    $this->news_model->set_comment();
    $this->load->view('news/success');
}   


}

}

dans routes.php

$route['news/comments'] = 'news/comments';

comment le résoudre ?impossible d'insérer des données dans la base de données en raison de l'erreur fatale.

OriginalL'auteur Ashish Singh | 2013-10-19