docs: protected void assertRange(int index, boolean allowLast) {
  		final int csize = expurge();
  		if (index < 0) {
  			throw new IndexOutOfBoundsException(Locale.getString("E1", index)); //$NON-NLS-1$
  		}
  		if (allowLast && (index > csize)) {
  			throw new IndexOutOfBoundsException(Locale.getString("E2", csize, index)); //$NON-NLS-1$
  		}
  		if (!allowLast && (index >= csize)) {
  			throw new IndexOutOfBoundsException(Locale.getString("E3", csize, index)); //$NON-NLS-1$
  		}
  	}