#NEWLINE# def group_by( self , * columns ) : #NEWLINE# #INDENT# '\n        Add a "group by" clause to the query\n\n        :param columns: The columns to group by\n        :type columns: tuple\n\n        :return: The current QueryBuilder instance\n        :rtype: QueryBuilder\n        ' #NEWLINE# for column in columns : #NEWLINE# #INDENT# self . groups . append ( self ) #NEWLINE# #UNINDENT# return self