old_contents: # recursive version of greatest common divisor
  # Euclidean algorithm
  
  def gcdRecur(a, b):
      if b == 0:
          return a
      else:
          t = a
          a = b
          b = t % b
          return gcdRecur(a, b)
new_contents: # recursive version of greatest common divisor
  # Euclidean algorithm
  
  def gcdRecur(a, b):
      # base case
      if b == 0:
          return a
      # recursive block
      else:
          t = a
          a = b
          b = t % b
          return gcdRecur(a, b)
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