Quick Sort

def sort(array):
  less = []
  equal = []
  greater = []

  if len(array) > 1:
    pivot = array[0]
    for x in array:
      if x < pivot:
        less.append(x)
      if x == pivot:
        equal.append(x)
      if x > pivot:
        greater.append(x)
    return sort(less) + equal + sort(greater)
  else:
    return array


print(sort([4,90,39,2,83,54]))