Why Can't I 'yield From' Inside An Async Function?

In Python 3.6, I am able to use yield inside a coroutine. However I am not able to use yield from. Below is my code. On line 3 I await another coroutine. On line 4 I try to yield

Solution 1:

According to PEP 525, which introduces asyncronous generators in Python 3.6:

Asynchronous yield from

While it is theoretically possible to implement yield from support for asynchronous generators, it would require a serious redesign of the generators implementation.

yield from is also less critical for asynchronous generators, since there is no need provide a mechanism of implementing another coroutines protocol on top of coroutines. And to compose asynchronous generators a simple async for loop can be used:

async def g1():
    yield 1
    yield 2

async def g2():
    asyncfor v ing1():
        yield v

As you can see, the answer boils down to "it would be too hard to implement, and you don't need it anyway".