CI_Form_validation::set_error_delimiters PHP Method

    public function set_error_delimiters($prefix = '<p>', $suffix = '</p>')
    {
        $this->_error_prefix = $prefix;
        $this->_error_suffix = $suffix;
        return $this;
    }

 function My_Form_validation()
 {
     parent::CI_Form_validation();
     parent::set_error_delimiters('<li>', '</li>');
 }