Timo Babst developed a generic ColumnsTransformer for the smart-data-lake repository, enabling flexible add, rename, and drop operations on data columns within ETL pipelines. Refactoring the previous AdditionalColumnsTransformer, Timo introduced updated class definitions and robust logic for column manipulation, all implemented in Scala and leveraging Spark for scalable data processing. Comprehensive unit tests were included to ensure reliability and maintainability. This work streamlines schema evolution and reduces ETL boilerplate, allowing for faster experimentation and easier maintenance. By focusing on reusable architecture and clear logic, Timo’s contribution improved the adaptability and efficiency of data engineering workflows in the project.