transformers

828044ca - Add Optional typing (#40686)

Add Optional typing (#40686) * Add Optional typing Signed-off-by: cyy <cyyever@outlook.com> * Fix typing Signed-off-by: cyy <cyyever@outlook.com> * Format Signed-off-by: cyy <cyyever@outlook.com> --------- Signed-off-by: cyy <cyyever@outlook.com>