Bubble Sort Algorithm in Python

import string
import os
import random

def bubbleSort(arr):
L = len(arr)-1
for j in range(L):
for i in range(L):
if arr[i]>=arr[i+1]:
ari = arr[i]
ari1 = arr[i+1]
arr[i]=ari1
arr[i+1]=ari
print(arr)
return arr

ar3 = [50,6,90,800,4,56,33,2100,400]
print(bubbleSort(ar3))