docs: def probably_identical(self):
          """
          :returns: Whether or not these two functions are identical.
          """
          if len(self._unmatched_blocks_from_a | self._unmatched_blocks_from_b) > 0:
              return False
          for (a, b) in self._block_matches:
              if not self.blocks_probably_identical(a, b):
                  return False
          return True