code: def _check_missing_slots(ob):
      
      missing_slots = tuple(
          filter(lambda s: not hasattr(ob, s), ob.__slots__),
      )
      if missing_slots:
          raise TypeError(
              'not all slots initialized in __init__, missing: {0}'.format(
                  missing_slots,
              ),
          )
docs: Check that all slots have been initialized when a custom __init__ method
      is provided.
  
      Parameters
      ----------
      ob : immutable
          The instance that was just initialized.
  
      Raises
      ------
      TypeError
          Raised when the instance has not set values that are named in the
          __slots__.