During December 2025, Yizhe Gao focused on backend reliability for the freqtrade/freqtrade repository, addressing a critical bug in the OKX exchange module’s price type mapping. Using Python and leveraging skills in API integration and unit testing, Yizhe corrected the mapping between PriceType.MARK and PriceType.INDEX to ensure accurate trading algorithm behavior. To reinforce this fix, Yizhe expanded unit test coverage for stop price type value mapping, directly improving the reliability of price-type handling. Additionally, Yizhe reverted an experimental test to align with an updated testing strategy, prioritizing continuous integration stability and maintaining a robust, well-documented test suite throughout the process.