input: Write a python function to sort the elements of an unsorted array using the bubble sort technique.
  assert bubbleSort([4, 5, 7, 3, 8, 1, 9]) == [1, 3, 4, 5, 7, 8, 9]
  assert bubbleSort([10, 2, 5, 3, 7, 6, 4]) == [2, 3, 4, 5, 6, 7, 10]
  assert bubbleSort([1, 2, 3, 4, 5, 6, 7]) == [1, 2, 3, 4, 5, 6, 7]
output: def bubbleSort(arr):
      n = len(arr)
      for i in range(n):
          for j in range(0, n-i-1):
              if arr[j] > arr[j+1]:
                  arr[j], arr[j+1] = arr[j+1], arr[j]
      return arr