Note that using % in a string will _always_ perform the sting substitutions, because the strings are constructed before the function is called. So log.debug('%s' % expensiveoperation()) will take about the same CPU time whether or not the logging level is DEBUG or INFO. if you use , no substitutions are performed unless the string is actually logged
Can now be used as so:
>>> msg['chat_state']
''
>>> msg
<message />
>>> msg['chat_state'] = 'paused'
>>> msg
<message>
<paused xmlns="http://jabber.org/protocol/chatstates" />
</message>
>>> msg['chat_state']
'paused'
>>> del msg['chat_state']
>>> msg
<message />
