 Complete the following phrase:  On 19 February 1937, two Eritreans made a failed assassination attempt on Rodolfo Graziani, the Viceroy of Italian East Africa and appointed Governor-General of Shewa during the Italian occupation of Ethiopia. In return, under carte blanche permission from the Federal Secretary , many Italian civilians, members of the military, and the paramilitary forces known as the Blackshirts conducted a three-day bloody reprisal in Addis Ababa. Known in Ethiopia as the 