How to set Environment Variable from secret file with pipenv

I need to set an Environment variable when running pipenv shell; however, I do not want to throw the variable into the .env file since it's from a secret file and I do not want to upload that to github.

Is there a way I could automatically set Environment Variables on "pipenv shell" using python imports? This way I could use the configparser library to pull variables from the secret file.

The reason I want to do this is so I can pull that environment variable into the docker-compose.yml file when in the python environment since I can't use python imports. Here is my docker-compose.yml file to give an idea of what I'm trying to do.

version: "3.9"

services:
  db:
    image: postgres
    ports:
      - "5432:5432"
    environment:
      - POSTGRES_DB=selenium-db
      - POSTGRES_USER=${DATABASE_USER}
      - POSTGRES_PASSWORD=${DATABASE_PASSWORD}
    volumes:
      - ./postgres-data:/var/lib/postgresql/data

As you can see I need a way of dynamically setting the DATABASE_USER and DATABASE_PASSWORD environment variables.