Worked on maintaining the Optuna repository with a focus on improving test reliability and continuous integration stability. Addressed a specific test-case violation by correcting float value handling in the test utilities, ensuring that type casting was accurate and reducing the occurrence of flaky test failures. The contribution involved targeted debugging and code refinement in Python, specifically within the test suite for visualization utilities. By enhancing the robustness of test utilities, the work supported more reliable CI processes for the project. The approach demonstrated careful attention to detail in testing practices and a solid understanding of Python and software testing methodologies.