New to Codeigniter Error issue with Login and Register code

did you extend CI_Model class also post the code here.

class model_users extends CI_Model{


public function __construct() 
     
           parent::__construct(); 
           $this->load->database();

public function can_log_in(){

$this->db->where('email',$this->input->post('email'));
$this->db->where('password',md5($this->input->post('password')));
$query = $this->db->get('user');

if ($query->num_rows()== 1){

return true;

}else{
return false;
}
}
}