def not_(self, other):
        if other is self:
            return other
        elif other is True:
            return False
        elif other is False:
            return True
        else:
            raise TypeError(type(other).__name__)
Although most layouts support margins, CustomLayout does not.
dataset/ETHPy150Open jek/flatland/flatland/util/base.py/Maybe.not_--crossover with--dataset/ETHPy150Open rwl/muntjac/muntjac/ui/custom_layout.py/CustomLayout.setMargin