The target python version for these examples is 3.6. Thus please install

sudo apt install python3.6-venv

which also should install python3.6 in that case. Then, create a virtual environment by running

python3.6 -m venv './venv'

Activate the working environment and if required bring it up to date

source ./venv/bin/activate
python -m pip install --upgrade pip

Then, finally install the requirements i.e. pyzmq and pycodestyle. The latter package is optional and is only required for linting hints in IDE's like the vscode editor.

pip install --requirement ./requirements.txt
pip freeze
pycodestyle==2.4.0
pyzmq==17.0.0
tornado==5.0.2

Furthermore, tornado asynchronous networking library is used for some code examples.

If you prefer to observe the communication on wire, say port tcp://*:5555, than ngrep and tcpdump can be used for this

sudo ngrep -d lo '' 'port 5555'

To capture the communication into the pcap file, please use

sudo tcpdump -i lo -n "port 5555" -w zmq-listening.pcap