code: private static Mode applyUMask(Mode mode, Mode umask) {
      mode.setOwnerBits(mode.getOwnerBits().and(umask.getOwnerBits().not()));
      mode.setGroupBits(mode.getGroupBits().and(umask.getGroupBits().not()));
      mode.setOtherBits(mode.getOtherBits().and(umask.getOtherBits().not()));
      return mode;
    }
docs: Applies the given umask {@link Mode} to this mode.
  
  @param mode the mode to update
  @param umask the umask to apply
  @return the updated object