if ( is == null ) throw new IllegalArgumentException( "The input stream must not be null" );
	public Module openModule( String fileName, InputStream is )			throws DesignFileException	{		Module module = GenericModuleReader.getInstance( ).read( this,				fileName, is );		assert module instanceof Library || module instanceof ReportDesign;		if ( module instanceof ReportDesign )			designs.add( module );		else			libraries.add( module );		return module;	}