Python 3.x Python中使用五个锁的问题

我不明白这部分，

使用self.locks[第一个]：
使用self.locks[秒]：

双嵌套的如何确定谁先选择左边的，谁先选择右边的

有人能解释一下订单是如何运作的吗

from threading import Lock


class DiningPhilosophers:
    def __init__(self):
        self.locks = [Lock() for _ in range(5)]

    # call the functions directly to execute, for example, eat()
    def wantsToEat(self, philosopher: int, pickLeftFork: 'Callable[[], None]',
                   pickRightFork: 'Callable[[], None]',
                   eat: 'Callable[[], None]',
                   putLeftFork: 'Callable[[], None]',
                   putRightFork: 'Callable[[], None]') -> None:
        if philosopher != 0:
            first, second = philosopher, (philosopher + 1) % 5
        else:
            second, first = philosopher, (philosopher + 1) % 5
        with self.locks[first]:
            with self.locks[second]:
                pickLeftFork()
                pickRightFork()
                eat()
                putLeftFork()
                putRightFork()