CI_Upload::display_errors PHP Method

    public function display_errors($open = '<p>', $close = '</p>')
    {
        return count($this->error_msg) > 0 ? $open . implode($close . $open, $this->error_msg) . $close : '';
    }

 /**
  * @param string $file_name
  * @return boolean
  */
 public function upload($file_name)
 {
     $path = $this->_nuevoDirectorio();
     $config = array('upload_path' => $path, 'allowed_types' => 'gif|jpg|png|bmp|doc|docx|pdf|xls|xlsx|txt|ppt|pptx|csv', 'max_size' => '0', 'max_width' => '0', 'max_height' => '0');
     $this->upload = new CI_Upload($config);
     if (!$this->upload->do_upload($file_name)) {
         rmdir($path);
         $this->_error = $this->upload->display_errors();
         return false;
     } else {
         $data = $this->upload->data();
         $relative_path = str_replace(realpath(BASEPATH . "../"), "", realpath($data["full_path"]));
         $relative_path = substr($relative_path, 1, strlen($relative_path));
         $insert = array("arch_c_tamano" => $data["file_size"], "arch_c_nombre" => $relative_path, "arch_c_mime" => $data["file_type"], "arch_c_hash" => $this->_fileHash(), "arch_f_fecha" => DATE("Y-m-d H:i:s"), "usu_ia_id" => $this->session->userdata('session_idUsuario'));
         $this->_archivo_model->query()->insert($insert);
         return true;
     }
 }