code: def constant_time_string_compare(a, b):
      
  
      try:
          return hmac.compare_digest(a, b)
      except AttributeError:
  
          if len(a) != len(b):
              return False
  
          result = 0
  
          for x, y in zip(a, b):
              result |= ord(x) ^ ord(y)
  
          return result == 0
docs: Helper for comparing string in constant time, independent
      of the python version being used.
  
      Args:
          a (str): A string to compare
          b (str): A string to compare