#NEWLINE# @ tornado . gen . coroutine #NEWLINE# def perform( self , ctx , propname , gentext ) : #NEWLINE# #INDENT# 'Do the work of the node, which boils down to calling\n        accum_append(), or maybe perform() recursively on subnodes.\n        ' #NEWLINE# ctx . accum_append ( ( '[Unimplemented GenNodeClass: %s]' % ( repr ( ctx ) , ) ) )