human
I wrote the below code

    if (bufsize is None):
        def reader():
            buf = []
            while True:
                data = (yield read(fd, 1024))
                if (not data):
                    break
                buf.append(data)
            (yield ReturnEvent(''.join(buf)))
        return DelegationEvent(reader())
    else:
        return ReadEvent(fd, bufsize)

What's a good function header?
 Here's a good function header?
assistant
#Here's a good function header.

def read(fd, bufsize=None):