'Return the parent scope.
:return: FoldScope or None'

def parent(self):

    if ((TextBlockHelper.get_fold_lvl(self._trigger) > 0) and self._trigger.blockNumber()):
        block = self._trigger.previous()
        ref_lvl = (self.trigger_level - 1)
        while (block.blockNumber() and ((not TextBlockHelper.is_fold_trigger(block)) or (TextBlockHelper.get_fold_lvl(block) > ref_lvl))):
            block = block.previous()
        try:
            return FoldScope(block)
        except ValueError:
            return None
    return None
