 Complete the following phrase:  After commissioning, the ship underwent a lengthy work up process, which was common for German destroyers during the Second World War. Following Z31 being damaged in a collision with a schooner on 6 November 1941, she was transferred to an operational flotilla in Norwegian waters in December 1942. On 30 December 1942, Z31 left Altafjord in northern Norway along with the heavy cruisers and Lützow and the destroyers Friedrich Eckoldt, Richard Beitzen, Theodor Riedel, and on Operation Regenbogen, an attempt to attack the 