php - Message: Undefined variable: datas

one text

i create code and then i have problem can show my data from data base to web, maybe you guys have solution for my problem,because i search this code and to fixing and cannot solve

controller\home.php

protected function __output($nview,$data=null)
    {
        
        $this->load->view('header',$data);
        $this->load->view($nview,$data);
        $this->load->view('footer');
    }

    public function showing() {

        $datas['data_arsip'] = $this->M_dataarsip->allDatasByDeveloperId($_session('id_user'));
        // $query = $this->db->query("SELECT * FROM data_arsip where developer_id = '".."'");
        // $datas['data_arsip'] =$query->getResult();
        return __output('main',$datas);
    }

model\M_dataarsip.php

class M_dataarsip extends CI_Model {


    public function allDatasByDeveloperId($developer_id){

        $query = $this->db->query("SELECT * FROM data_arsip where developer_id = '$developer_id'");
        return $query->result();
    }
}

html

                    <?php
                            foreach($datas as $a) {
                            echo "<tr>";
                            echo "<td>".$a['noarsip']."</td>";
                            echo "<td>".$a['tanggal']."</td>";
                            echo "<td>".$a['nama_kode']."</td>";
                            echo "<td>".$a['uraian']."</td>";
                            echo "<td>".$a['ket']."</td>";
                            if($a['file']=="") {
                                echo "<td></td>";
                            }else {
                                echo "<td><a href='".base_url('files/'.$a['file'])."' target='_blank'><span class='glyphicon glyphicon-save' aria-hidden='true'></span></a></td>";
                            }
                            echo "<td>".$a['jumlah']."</td>";
                            echo "<td>".$a['nobox']."</td>";
                            echo "<td ".($a['f']=='sudah'?"class='danger'":"").">".$a['b']."</td>";
                            echo "<td><a href='".site_url('home/view/'.$a['id'])."' ><i class=\"glyphicon glyphicon-search\"></i></a></td>";
                            echo "<td>";
                            if(isset($_SESSION['akses_modul']['entridata']) && $_SESSION['akses_modul']['entridata']=='on') {
                                echo "<a href='".site_url('/admin/vedit/'.$a['id'])."'><span class='glyphicon glyphicon-pencil' aria-hidden='true'></span></a>";
                            }
                            echo "</td>";
                            echo "<td>";
                            if(isset($_SESSION['akses_modul']['entridata']) && $_SESSION['akses_modul']['entridata']=='on') {
                                echo "<a class='deldata' id='".$a['id']."' href='#' data-toggle=\"modal\" data-target=\"#deldata\"><i class=\"glyphicon glyphicon-trash\"></i></a>";
                            }
                            echo "</td>";
                            echo "</tr>";
                        }
                    ?>