def sort(array=[12, 4, 5, 6, 7, 3, 1, 15]):
    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)
Quicksort with Python