code: def add_uuid(dom, uuid):
      
      mods_tag = get_mods_tag(dom)
  
      uuid_tag = dhtmlparser.HTMLElement(
          "mods:identifier",
          {"type": "uuid"},
          [dhtmlparser.HTMLElement(uuid)]
      )
  
      insert_tag(uuid_tag, dom.find("mods:identifier"), mods_tag)
docs: Add ``<mods:identifier>`` with `uuid`.