code: def bonus_damage(self):
          
          # TODO Consider unit with ability attacks like Oracle, Thor, Baneling
          if self._weapons:
              for weapon in self._weapons:
                  if weapon.damage_bonus:
                      b = weapon.damage_bonus[0]
                      return b.bonus, b.attribute
docs: Returns a tuple of form 'bonus damage, armor type' if unit does bonus damage against armor type
          Light = 1; Armored = 2; Biological = 3; Mechanical = 4; Robotic = 5; Psionic = 6; Massive = 7;
          Structure = 8; Hover = 9; Heroic = 10; Summoned = 11