Lewis & Short

dē-sūmo, mpsi (msi), 3, v. a. Lit., to take for one’s self from a multitude or mass; hence, to pick out, choose, select (syn. deligere); to take upon one’s self, undertake (rare, and perh. not ante-Aug.— syn. suscipere): sibi consules asservandos desumunt, Liv. 4, 55, 3: sibi hostes, id. 38, 45; cf.: sibi pugnas, Tac. Or. 37; and: cursum certamenque, Plin. Ep. 8, 20, 7: sibi vacuas Athenas, *Hor. Ep. 2, 2, 81.