#NEWLINE# def _timestamp_message( self , attrs ) : #NEWLINE# #INDENT# 'Add a timestamp to ``attrs``, if the topic is so configured.\n\n        If ``attrs`` already has the key, do nothing.\n\n        Helper method for ``publish``/``Batch.publish``.\n        ' #NEWLINE# if ( self . timestamp_messages and ( 'timestamp' not in attrs ) ) : #NEWLINE# #INDENT# attrs [ 'timestamp' ] = _datetime_to_rfc3339 ( _NOW ( ) )