code: function(graph, cells)
  	{
  		cells = cells || graph.getSelectionCells();
  		var result = graph.getExportableCells(graph.model.getTopmostCells(cells));
  		mxClipboard.insertCount = 1;
  		mxClipboard.setCells(graph.cloneCells(result));
  
  		return result;
  	}
docs: Function: copy
  
  Copies the given array of <mxCells> from the specified
  graph to <cells>. Returns the original array of cells that has
  been cloned. Descendants of cells in the array are ignored.
  
  Parameters:
  
  graph - <mxGraph> that contains the cells to be copied.
  cells - Optional array of <mxCells> to be copied.