input: def bubble_sort(arr): 
      n = len(arr) 
      for i in range(n-1):
          for j in range(0, n-i-1): 
              if arr[j] > arr[j+1] : 
                  arr[j], arr[j+1] = arr[j+1], arr[j] 
  
      """Sort a given array in ascending order using the bubble sort algorithm.
      >>> bubble_sort([3, 7, 4, 1])
      Sorted array :
      1
      3
      4
      7
      """
output:     print("Sorted array :")
      for i in range(n):
          print(arr[i])