Colored logging messages from Python script within GitLab CI

I am using a docker container for my GitLab CI and would like to have any output/logging messages in color inside the CI. What I mean: the commands from .gitlab-ci.yml are in color, but the outputs of the scripts running python3 colored_logging.py are not.

It is so cumbersome to dig through bigger logs without any colors :-(

Here is an example project on GitLab:
https://gitlab.com/ziggyler.ziegler/non-colored-ci/-/jobs/1873125969

Does somebody know how to get colored logging messages in lines 113-117?
Any hints?

Thank you!

Actual output

Desired output

My Dockerfile:

FROM python:3.6

ENV TERM xterm-256color

RUN apt-get update && rm -rf /var/lib/apt/lists/*

RUN pip3 install loguru

My .gitlab-ci.yml:

image: docker:19.03.12

services:
  - docker:19.03.12-dind

stages:
  - build
  - run

build:
    stage: build
    rules:
      - if: $CI_PIPELINE_SOURCE == "push" && $CI_COMMIT_BRANCH
        changes:
          - Dockerfile
    before_script:
        - docker login -u $CI_REGISTRY_USER -p $CI_REGISTRY_PASSWORD $CI_REGISTRY
    script:
        - docker build --cache-from $CI_REGISTRY_IMAGE:latest --tag $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA --tag $CI_REGISTRY_IMAGE:latest .
        - docker push $CI_REGISTRY_IMAGE:$CI_COMMIT_SHA
        - docker push $CI_REGISTRY_IMAGE:latest

run:
    stage: run
    image: $CI_REGISTRY_IMAGE:latest
    script:
        - ls -la
        - python3 colored_logging.py

My Python code to create the logging messages:
from loguru import logger

logger.debug("This is a debug message!")
logger.info("This is an info logging message!")
logger.warning("This is a waring and should appear in yellow color!")
logger.error("This is an error in red color!")
logger.critical("This is a very critical message!")


Set the LOGURU_COLORIZE variable in your Docker container.
run:
stage: run
image: $CI_REGISTRY_IMAGE:latest
variables:
LOGURU_COLORIZE: "true"
script:
- ls -la
- python3 colored_logging.py


StackExchange DevOps Q#15132, answer score: 7