bug-fix/NaN error in examples

[zsdqui]

Pull request recommendations:

• [ ] Name your pull request your-development-type/short-description. Ex: feature/read-tiff-files
• [ ] Link to any relevant issue in the PR description. Ex: Resolves [gh-12], adds tiff file format support
• [ ] Provide context of changes.
• [ ] Provide relevant tests for your feature or bug fix.
• [ ] Provide or update documentation for any feature added by your pull request.

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