python yield from 反向迭代，迭代代码

from collections import deque


class LindeHistory:
    def __init__(self, lines, histlen=3):
        self.lines = lines
        self.history = deque(maxlen=histlen)

    def __iter__(self):
        yield from (line for _, line in enumerate(self.lines, 1))

    def __reversed__(self):
        yield from (self.lines[line] for line in range(len(self.lines) - 1, -1, -1))

    def clear(self):
        self.history.clear()


lines = ['morgan', 'lions'] * 10
for x in reversed(LindeHistory(lines)):
    print(x)

iter 迭代器
reversed 反向迭代