python中yield from怎么用？

本文教程操作环境：windows7系统、Python 3.9.1，DELL G3电脑。

yield from本质：

for item in iterable: yield item的缩写版

代码示例：

def g(x):
    yield from range(x , 0, -1)
    yield from range(x)
print(list(g(5)))

利用yield from语句向生成器（协程）传送数据：

def writer():
    while True:
        w = (yield) 
        print('>>', w)
def writer_wrapper(coro1):
coro1.send(None) 
    while True:
        try:
            x = (yield) 
            coro1.send(x) 
        except StopIteration:
            pass
def writer_wrapper(coro2):
yield from coro2