assert slotID != DesignElement.NO_SLOT;
assert slotID != IDesignElementModel.NO_SLOT;
	private List sortVisibleElements( List nameSpaceList, int level )	{		// Sort element in namespace		List modules = new ArrayList( );		if ( nameSpaceList.size( ) == 0 )			return modules;		// Check value in design handle and libraries.		DesignElement element = (DesignElement) nameSpaceList.get( 0 );		int slotID = element.getContainerSlot( );		assert slotID != DesignElement.NO_SLOT;		// Libraries		modules.add( this );		modules.addAll( getLibraries( level ) );				return checkVisibleElements( nameSpaceList, modules, slotID );	}