bug in evaluations.py

[KohlerHECTOR]

Fixes #441

Description

Please include a summary of the change and which issue is fixed. Please also include relevant motivation and context, in particular link the relevant issue if it is appropriate. List any dependencies that are required for this change.

Checklist

• [X] My code follows the style guideline To check : black --check examples rlberry *py flake8 --select F401,F405,D410,D411,D412 --exclude=rlberry/check_packages.py --per-file-ignores="init.py:F401",
• [X] I have commented my code, particularly in hard-to-understand areas,
• [X] I have made corresponding changes to the documentation,
• [ ] I have added tests that prove my fix is effective or that my feature works,
• [ ] New and existing unit tests pass locally with my changes,
• [ ] If updated the changelog if necessary,
• [X] I have set the label "ready for review" and the checks are all green.

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