func_code: def quicksort(a):
      less = []
      equal = []
      greater = []
      if len(a) > 1:
          pivot = a[0]
          for x in a:
              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 a