Below are some basic python dependency management steps. that can be used to control your python work.
New Project
If your starting a new python script/function/module/package you’ll properly want to create one or many virtual environments I like virtualenv (read my post here about setting this up)
Install dependencies
Next you’ll want to install some modules/packages to support your work
python3 -m pip install x y z
Save dependencies
After installing we will want to save them to a requirements.txt for future builds / setups
python3 -m pip freeze > requirements.txt
Load dependencies from requirements
If you have a requirements.txt file you can then load all dependencies in a single command via
python3 -m pip install -r requirements.txt