test_detism_scope(1) = 1
test_detism_scope(11) = 1
test_detism_scope(21) = 21
test_switch_scope(f1) = []
test_switch_scope(f2) = [1, 2]
test_switch_scope(f3(10)) = [3, 10, 11]
test_switch_scope(f3(20)) = [3, 20, 21]
test_switch_arms_detism_scope(f1) = [101, 1101]
test_switch_arms_detism_scope(f1) = [101, 1101]
test_switch_arms_detism_scope(f3(10)) = [110, 1110]
test_switch_arms_detism_scope(f3(20)) = []