code: public static function createSnippet(string $snptName): ?Snippet
      {
          $snptRoot = AppHelper::getInstance()->getComponentRoot('snippets');
          $snptFile  = $snptRoot.\DIRECTORY_SEPARATOR
              .strtolower($snptName).'.php';
          if (is_readable($snptFile)) {
              return new Snippet($snptFile);
          }
          return null;
      }
docs: The method creates a snippet-object.
  @param type $snptName The snippet name.
  @return \nadir2\core\Snippet|null. It returns null if snippet file isn't
  readable.