public function get_by_bit(string $id): ?array
  {
    $t =& $this;
    if ( \bbn\str::is_uid($id) ){
      return $this->db->rselect([
        'table' => $this->class_cfg['table'],
        'fields' => array_map(function($v) use($t){
          return $this->class_cfg['table'].'.'.$v;
        }, array_values($this->class_cfg['arch']['user_options'])),
        'join' => [[
          'table' => $this->class_cfg['tables']['user_options_bits'],
          'on' => [
            'conditions' => [[
              'field' => $this->class_cfg['arch']['user_options_bits']['id_user_option'],
              'exp' => $this->class_cfg['table'].'.'.$this->fields['id']
            ]]
          ]
        ]],
        'where' => [
          $this->class_cfg['tables']['user_options_bits'].'.'.$this->class_cfg['arch']['user_options_bits']['id'] => $id
        ]
      ]);
    }
  }