Worked on the ROCm/flash-attention repository, delivering a targeted refactor to standardize optional type usage throughout the codebase. The effort involved replacing c10::optional with std::optional in flash_attn functions, enhancing API clarity and ensuring better compatibility with standard C++ libraries. This change was implemented using C++ and CUDA, with a focus on low-level optimization and template metaprogramming techniques. The refactor maintained existing functionality while improving maintainability and aligning the code with modern C++ practices. No bugs were addressed during this period, as the work concentrated on feature improvement and code consistency rather than introducing new features or fixing defects.