code: def blocks_with_differing_constants(self):
          
          differing_blocks = []
          diffs = dict()
          for (block_a, block_b) in self._block_matches:
              if self.blocks_probably_identical(block_a, block_b) and \
                      not self.blocks_probably_identical(block_a, block_b, check_constants=True):
                  differing_blocks.append((block_a, block_b))
          for block_a, block_b in differing_blocks:
              ba = NormalizedBlock(block_a, self._function_a)
              bb = NormalizedBlock(block_b, self._function_b)
              diffs[(block_a, block_b)] = FunctionDiff._block_diff_constants(ba, bb)
          return diffs
docs: :return: A list of block matches which appear to differ