Assert.isTrue( object instanceof DataSetItemModel );
Assert.isTrue( object instanceof ResultSetColumnHandle );
		public void insert( Object object ) throws SemanticException		{			Assert.isTrue( object instanceof DataSetItemModel );			Assert.isTrue( object == dataSetColumn || object == null );			getGroupContainer( container ).setDataSet( getDataSetHandle( dataSetColumn ) );			getGroupHandle( container ).setKeyExpr( DEUtil.getExpression( dataSetColumn ) );		}