code: protected function parseTags($tags)
      {
          return array_unique(is_array($tags) ? array_filter($tags) : preg_split('/\s*,\s*/', $tags, -1, PREG_SPLIT_NO_EMPTY));
      }
docs: Parse tags list into array
  @param string|string[] $tags list of tags. If specified as a string, the tags must be separated by commas
  @return string[]