old_contents: from random import randint
  
  from pyalgs.algorithms.commons.util import exchange
  
  
  class KnuthShuffle(object):
      @staticmethod
      def shuffle(a):
          for i in range(1, len(a)):
              r = randint(0, i+1)
              exchange(a, r, i)
  
new_contents: from random import randint
  
  from pyalgs.algorithms.commons.util import exchange
  
  
  class KnuthShuffle(object):
      @staticmethod
      def shuffle(a):
          for i in range(1, len(a)):
              r = randint(0, i)
              exchange(a, r, i)
  
subject: fix the array index out of range for the shuffling