small fixing with local variable

[Ipuch]

This change is 

[codecov[bot]]

Codecov Report

Base: 0.00% // Head: 0.00% // No change to project coverage :thumbsup:

Coverage data is based on head (b24a5e7) compared to base (dd23c24). Patch coverage: 0.00% of modified lines in pull request are covered.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #88 +/- ## ====================================== Coverage 0.00% 0.00% ====================================== Files 10 10 Lines 2623 2625 +2 ====================================== - Misses 2623 2625 +2 ``` | [Impacted Files](https://codecov.io/gh/pyomeca/bioviz/pull/88?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pyomeca) | Coverage Δ | | |---|---|---| | [bioviz/\_version.py](https://codecov.io/gh/pyomeca/bioviz/pull/88?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pyomeca#diff-Ymlvdml6L192ZXJzaW9uLnB5) | `0.00% <0.00%> (ø)` | | | [bioviz/biorbd\_vtk.py](https://codecov.io/gh/pyomeca/bioviz/pull/88?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pyomeca#diff-Ymlvdml6L2Jpb3JiZF92dGsucHk=) | `0.00% <0.00%> (ø)` | | Help us with your feedback. Take ten seconds to tell us [how you rate us](https://about.codecov.io/nps?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pyomeca). Have a feature suggestion? [Share it here.](https://app.codecov.io/gh/feedback/?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pyomeca)

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