During May 2025, Sofia Soares focused on improving data reliability in the piotrplenik/pandas repository by addressing a bug in HDFStore’s select() method. She replaced the previous searchsorted approach with np.flatnonzero to ensure correct index retrieval for categorical string columns, directly enhancing the accuracy of data queries in analytics pipelines using HDF5-backed storage. Sofia implemented this fix using Python and Cython, and reinforced it with a dedicated regression test to prevent future issues. Her work demonstrated careful attention to data handling and testing, resulting in a robust solution that reduced user-reported anomalies and improved the integrity of data operations.