code: def test_difference_random(self):
      seed(42)
      for rep in range(10):
          for string_length in range(1, 100, 10):
              bitstring_1 = self.random_bitstring(string_length)
              bitstring_2 = self.random_bitstring(string_length)
              target = "0b"
              for bit_1, bit_2 in zip(bitstring_1[2:], bitstring_2[2:]):
                  if bit_1 == "1" and bit_2 == "0":
                      target += "1"
                  else:
                      target += "0"
              self.assert_difference(bitstring_1, bitstring_2, target)
  
imports: import unittest
  from copy import deepcopy
  from random import randint, random, seed
  from lightly.api.bitmask import BitMask
label_desc: Use image node_id 13 for calling the TestBitMask obj's underlying member method code with example usage: obj.test_difference_random() without return types