F modes(values)
DefaultDict[Int, Int] count
L(v) values
count[v]++
V best = max(count.values())
R count.filter(kv -> kv[1] == @best).map(kv -> kv[0])
print(modes([1, 3, 6, 6, 6, 6, 7, 7, 12, 12, 17]))
print(modes([1, 1, 2, 4, 4]))