Install dependencies from setup.py

Just create requirements.txt in your lib folder and add all dependencies like this:

gunicorn
docutils>=0.3
lxml==0.5a7

Then create a setup.py script and read requirements.txt:

import os
lib_folder = os.path.dirname(os.path.realpath(__file__))
requirement_path = f"{lib_folder}/requirements.txt"
install_requires = [] # Here we'll add: ["gunicorn", "docutils>=0.3", "lxml==0.5a7"]
if os.path.isfile(requirement_path):
    with open(requirement_path) as f:
        install_requires = f.read().splitlines()
setup(name="mypackage", install_requires=install_requires, [...])

The execution of python setup.py install will install your package and all dependencies. Like @jwodder said it is not mandatory to create a requirements.txt file, you can just set install_requires directly in the setup.py script. But writing a requirements.txt file is a best practice.

In the setup function call, you also have to set version, packages, author, etc, read the doc for a complete example: https://docs.python.org/3/distutils/setupscript.html

Your package directory should look like this:

├── mypackage
│   ├── mypackage
│   │   ├── __init__.py
│   │   └── mymodule.py
│   ├── requirements.txt
│   └── setup.py