code: public function set($key, $value)
      {
          $meta = $this->metaModel::where('key', $key)->first();
  
          if ($meta === null) {
              $meta = new $this->metaModel;
              $meta->key = $key;
          }
  
          $meta->value = $value;
  
          $meta->save();
      }
docs: Set meta at given key
  for package realm.
  If meta exists, it'll be overwritten.
  
  @param string $key
  @param mixed  $value