I am trying to implement quicksort.
I do not know how to concatenate the three arrays and printing them.
Could someone please help me complete my code?
 
def sort(array=[2,5,1,6,9,8,7,10,21,12]):
    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)
            sort(less)
            sort(pivot)
            sort(greater)