entry missing in secure_tuple's default value in client_nb.py
Reported by jurek:
The library errors out when trying to create a new XMPP connection without specifying an explicit secure_tuple.
There is one entry missing in the default value of secure_tuple in the connect method of NonBlockingClient.
When unpacking secure_tuple, five entries are expected, but only four are given in the default value in the method declaration.
Add another None entry in the method declaration.