def blog__clean_tag_parents
      tag_parents = LatoBlog::TagParent.all
      tag_parents.map { |tp| tp.destroy if tp.tags.empty? }
    end
def blog__clean_tag_parents
      tag_parents = LatoBlog::TagParent.all
      tag_parents.map { |tp| tp.destroy if tp.tags.empty? }
    end
This function cleans all old tag parents without any child.