$ sudo apt-get update
$ sudo apt-get install python-sleekxmpp 

python-sleekxmpp is installed in your system.

Make ensure the python-sleekxmpp package were installed using the commands given below,

$ sudo dpkg-query -l | grep python-sleekxmpp *

You will get with python-sleekxmpp package name, version, architecture and description in a table

python-sleekxmpp package basic information: