code: def _issubclass(sub, sup):
      '''Safe issubclass().
      '''
      if sup is not object:
          try:
              return issubclass(sub, sup)
          except TypeError:
              pass
      return Falsf _issubclass(sub, sup):
      '''Safe issubclass().
      '''
      if sup is not object:
          try:
              return issubclass(sub, sup)
          except TypeError:
              pass
      return False
docs: Safe issubclass().