code: @Nonnull
    public EChange renameUserGroup (@Nullable final String sUserGroupID, @Nonnull @Nonempty final String sNewName)
    {
      // Resolve user group
      final UserGroup aUserGroup = getOfID (sUserGroupID);
      if (aUserGroup == null)
      {
        AuditHelper.onAuditModifyFailure (UserGroup.OT, sUserGroupID, "no-such-usergroup-id", "name");
        return EChange.UNCHANGED;
      }
  
      m_aRWLock.writeLock ().lock ();
      try
      {
        if (aUserGroup.setName (sNewName).isUnchanged ())
          return EChange.UNCHANGED;
  
        BusinessObjectHelper.setLastModificationNow (aUserGroup);
        internalUpdateItem (aUserGroup);
      }
      finally
      {
        m_aRWLock.writeLock ().unlock ();
      }
      AuditHelper.onAuditModifySuccess (UserGroup.OT, "name", sUserGroupID, sNewName);
  
      // Execute callback as the very last action
      m_aCallbacks.forEach (aCB -> aCB.onUserGroupRenamed (aUserGroup));
  
      return EChange.CHANGED;
    }
docs: Rename the user group with the specified ID
  
  @param sUserGroupID
  The ID of the user group. May be <code>null</code>.
  @param sNewName
  The new name of the user group. May neither be <code>null</code> nor
  empty.
  @return {@link EChange#CHANGED} if the user group ID was valid, and the new
  name was different from the old name