Also I don't need to modify your CMakeList for a python node so I would firstly get rid of that. I would then use the chmod + command again just to make sure that your node is executable. After that go to your catkin_ws directory and type the catkin_make. After this in your home directory and use the following command : source ~/type your path to/catkin_ws/devel/setup.bash. Did this solve your problem?