For #11 add F_from_IC.
For #11 add IC_from_CD_helper.
For #11 add IC_from_CD.
For #11 add IC_from_F and CD_from_IC.
For #11 add J_from_IC.
For #11 convert resulting flag to IC vector (but not confident value is correct.
For #11 fix confusing TYPO - wrote join_cd when join_ic was meant.
For #11 add J_from_CD (but not confident value is correct).