python3-dotenv (Read key-value pairs from .env file and set env. vars)

python3-dotenv reads key-value pairs from a .env file and can set them
as environment variables. It helps in the development of applications
following the 12-factor principles.

NOTE: If you want cli to work, have "click" installed before buildling.

NOTE: 1.2.1 is last version to support python-3.9
