Bug 183918 get relative file path of linkage library
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/LibraryHandle.java
.newTheme( themeName );
			try
			{
				getThemes( ).add( newTheme );
			}
			catch ( ContentException e )
			{
				assert false;
			}
			catch ( NameException e )
			{
				assert false;
			}
			theme = (Theme) newTheme.getElement( );
		}
		try
		{
			if ( libElement.getThemeName( ) == null )
				setThemeName( themeName );
		}
		catch ( SemanticException e )
		{
			assert false;
		}
		return (ThemeHandle) theme.getHandle( module );
	}
	/**
	 * Imports the selected styles in a <code>CssStyleSheetHandle</code> to
	 * the given theme of the library. Each in the list is instance of
	 * <code>SharedStyleHandle</code> .If any style selected has a duplicate