def next(self):
        if not self.hasNext():
            return None

        while self.cur:
            self.stk.append(self.cur)
            self.cur = self.cur.left

        node = self.stk.pop()  # left_most
        self.cur = node.right
        return node
``create_test_db`` implementation that skips both creation and flushing.
dataset/ETHPy150Open algorhythms/LintCode/Implement Iterator of Binary Search Tree.py/Solution.next--crossover with--dataset/ETHPy150Open django-nose/django-nose/django_nose/runner.py/_skip_create_test_db