Before we actually get started, it is important to know how to install a package properly. There are at least four different options for installing a package. The first and most obvious is by using the plain pip command:

pip install package

This can also be achieved by using setup.py directly:

cd package
python setup.py install

This installs the package within your Python environment which would be the likely virtualenv/venv if you are using it or the global environment otherwise.

For development however, this is not recommended. To test your code, you would need to either reinstall the package for every test or modify the files within the Python's site-packages directory, which would mean it would be outside of your revision control system as well. That's where the development installs come in; instead of copying the package files to the Python package directory, they simply install a link within the site-packages directory to the path where the package is actually located. This allows you to modify the code and immediately see the results in the scripts and applications you run without the need to reinstall your code after each change.

As is the case with a regular install, both pip and setup.py versions are available:

pip install –e package_directory

And the setup.py version:

cd package_directory
python setup.py develop