code: public static MamManager getInstanceFor(MultiUserChat multiUserChat) {
          XMPPConnection connection = multiUserChat.getXmppConnection();
          Jid archiveAddress = multiUserChat.getRoom();
          return getInstanceFor(connection, archiveAddress);
      }
docs: Get a MamManager for the MAM archive of the given {@code MultiUserChat}. Note that not all MUCs support MAM,
  hence it is recommended to use {@link #isSupported()} to check if MAM is supported by the MUC.
  
  @param multiUserChat the MultiUserChat to retrieve the MamManager for.
  @return the MamManager for the given MultiUserChat.
  @since 4.3.0