private function convertTypeToServiceClassName(string $category, string $type): ?string
  {
    if( class_exists($type)) { // custom service
      return $type;
    }
    else {
      $type = $this->kernel->config()->namespaces->services . ucfirst(strtolower($category))."\\Adapters\\".ucfirst(strtolower($type));
      if(class_exists($type)) { // standard service
        return $type;
      }
    }
    return null;
  }