def _dequeue(self):
        position, show = self.show_hide_queue.popitem(last=False)
        shown = position in self._shown
        if show and not shown:
            self._show_block(position, self.objects[position])
        elif shown and not show:
            self._hide_block(position)
Compute new table expression with the indicated column expressions from
dataset/ETHPy150Open traverseda/pycraft/pycraft/world.py/World._dequeue--crossover with--dataset/ETHPy150Open cloudera/ibis/ibis/expr/api.py/projection