Quick Sort

def quick_sort(collection):
    length = len(collection)
    if length <= 1:
        return collection
    else:
        pivot = collection.pop()
        greater, lesser = [], []
        for element in collection:
            if element > pivot:
                greater.append(element)
            else:
                lesser.append(element)
        return quick_sort(lesser) + [pivot] + quick_sort(greater)