Complex sentence: Micheline Aline "Michou" Dumon (20 May 1921--16 November 2017) was a Belgian wartime resistance agent in WWII with the Comet Line (Réseau Comète) that went by the codenames "Michou" or "Lily".
Split into simpler sentences: Micheline Aline "Michou" Dumon (20 May 1921--16 November 2017) was a member of the Belgian Resistance during World War II with the Comet line (Réseau Comète). She went by the codenames "Michou" or "Lily".