add cartouche in README.md

python/quality/package_black/README.md

 ## Objective
 
-Run [Black](https://github.com/psf/black) on your Python code to ensure it complies with the coding style
-guide.
+Run [Black](https://github.com/psf/black) on your Python code to ensure it complies with the coding
+style guide.
 
 ## How to use it
 
 1. Create a [python package](https://packaging.python.org/en/latest/tutorials/packaging-projects/).
 2. Include template in your CI/CD conf (see quick use above)
 3. Customize the template if it's relevant
+
+## Add <a href="https://github.com/psf/black"><img alt="Code style: black" src="https://img.shields.io/badge/code%20style-black-000000.svg"></a> cartouche to your project README.md
+```markdown
+<a href="https://github.com/psf/black">
+    <img alt="Code style: black" src="https://img.shields.io/badge/code%20style-black-000000.svg">
+</a>
+```
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