Sorry for the misunderstanding, here is the complete example:

socket.setblocking(0)

try:
	buffer = socket.recv()

	if not buffer:
		break

except OSError:
	bytes_sent = socket.send(b'a' * 32 * 1024 * 1024)

In this case the socket is ready for sending data and should return the bytes that were actually sent. But when sending a large amount of bytes it every time fails with SSLWantWriteError exception.