code: public static synchronized void removeChannelGroup(String groupId) {
          try {
              if (_removeChannelGroup(groupId)) {
                  save();
              }
          } catch (Exception ex) {
              Log.e(WonderPush.TAG, "Unexpected error while removing channel group " + groupId, ex);
          }
      }
docs: Remove a channel group.
  
  <p>Remove a channel group both from this class registry and from Android.</p>
  
  @param groupId The identifier of the channel group to remove.