def append_element(self, *args, **kwargs):
        assert not self._ready or isinstance(self._values, list), (
            '_CallbackResult state is incompatible with append_element: '
            'ready=%r; values=%r' % (self._ready, self._values))

        try:
            value = self._value_class(*args, **kwargs)
        except Exception:
            LOGGER.error(
                "append_element failed: value_class=%r; args=%r; kwargs=%r",
                self._value_class, args, kwargs)
            raise

        if self._values is None:
            self._values = [value]
        else:
            self._values.append(value)

        self._ready = True
Return the ballot as an internal ballot string.
dataset/ETHPy150Open pika/pika/pika/adapters/blocking_connection.py/_CallbackResult.append_element--crossover with--dataset/ETHPy150Open cjerdonek/open-rcv/openrcv/formats/internal.py/to_internal_ballot