For python scripts to be invoked from command line, consider #!/usr/bin/env python

[Johann Petrak]

Currently the scripts, like parzu_server.py or parzy.py use the shebang line
#!/usr/bin/python which will always invoke the system-installed python command (which depending on the system may be Python 2 or 3).
However, many users have a per-user python command e.g. to make "python" default to python3 instead of Python 2 or they their own Anaconda installation within their user space where all the python packages are installed and new ones can be installed without administrator access.

Using #!/usr/bin/env python would make use of those per-user python commands but would still use the default /usr/bin/python if no per-user python command exists (essentially just uses what is in the PATH).