private function PreviousItem()
    {
        $this->previous = $this->GetTreeItem('previous');
        return $this->previous->Exists() ? $this->previous : null;
    }
private function PreviousItem()
    {
        $this->previous = $this->GetTreeItem('previous');
        return $this->previous->Exists() ? $this->previous : null;
    }
private function PreviousItem ( ) { $ this -> previous = $ this -> GetTreeItem ( 'previous' ) ; return $ this -> previous -> Exists ( ) ? $ this -> previous : null ; }
The previous item
@return TemplateObject
The previous item