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 />
