AttributeError when sasl_auth mechanism is being processed

[wrouesnel]

16:58:22 ERROR    sleekxmpp.xmlstream.xmlst Error processing stream handler: Stream Features
Traceback (most recent call last):
  File "/usr/local/lib/python3.5/dist-packages/sleekxmpp/xmlstream/xmlstream.py", line 1684, in _event_runner
    handler.run(args[0])
  File "/usr/local/lib/python3.5/dist-packages/sleekxmpp/xmlstream/handler/callback.py", line 76, in run
    self._pointer(payload)
  File "/usr/local/lib/python3.5/dist-packages/sleekxmpp/clientxmpp.py", line 285, in _handle_stream_features
    if handler(features) and restart:
  File "/usr/local/lib/python3.5/dist-packages/sleekxmpp/features/feature_mechanisms/mechanisms.py", line 163, in _handle_sasl_auth
    return self._send_auth()
  File "/usr/local/lib/python3.5/dist-packages/sleekxmpp/features/feature_mechanisms/mechanisms.py", line 172, in _send_auth
    min_mech=self.min_mech)
  File "/usr/local/lib/python3.5/dist-packages/sleekxmpp/util/sasl/client.py", line 163, in choose
    creds[cred] = bytes(saslprep(creds[cred]))
  File "/usr/local/lib/python3.5/dist-packages/sleekxmpp/util/stringprep_profiles.py", line 139, in profile
    data = unicode(data)
  File "/usr/local/lib/python3.5/dist-packages/sleekxmpp/util/misc_ops.py", line 12, in unicode
    return text.decode('utf-8')
AttributeError: 'tuple' object has no attribute 'decode'
16:58:22 ERROR    sleekxmpp.xmlstream.stanz Error handling {jabber:client}features stanza
Traceback (most recent call last):
  File "/usr/local/lib/python3.5/dist-packages/sleekxmpp/xmlstream/xmlstream.py", line 1684, in _event_runner
    handler.run(args[0])
  File "/usr/local/lib/python3.5/dist-packages/sleekxmpp/xmlstream/handler/callback.py", line 76, in run
    self._pointer(payload)
  File "/usr/local/lib/python3.5/dist-packages/sleekxmpp/clientxmpp.py", line 285, in _handle_stream_features
    if handler(features) and restart:
  File "/usr/local/lib/python3.5/dist-packages/sleekxmpp/features/feature_mechanisms/mechanisms.py", line 163, in _handle_sasl_auth
    return self._send_auth()
  File "/usr/local/lib/python3.5/dist-packages/sleekxmpp/features/feature_mechanisms/mechanisms.py", line 172, in _send_auth
    min_mech=self.min_mech)
  File "/usr/local/lib/python3.5/dist-packages/sleekxmpp/util/sasl/client.py", line 163, in choose
    creds[cred] = bytes(saslprep(creds[cred]))
  File "/usr/local/lib/python3.5/dist-packages/sleekxmpp/util/stringprep_profiles.py", line 139, in profile
    data = unicode(data)
  File "/usr/local/lib/python3.5/dist-packages/sleekxmpp/util/misc_ops.py", line 12, in unicode
    return text.decode('utf-8')
AttributeError: 'tuple' object has no attribute 'decode'

Observed while trying to connect to a hipchat XMPP server with errbot., using a slightly patched 1.3.3 release to work around the SSL date parsing issue. Observed with 1.3.1 as well.