try:

import select

import select_impl

return select_impl.SelectProactor

except ImportError:

try:

import select

if select and hasattr(select, 'poll'):

import poll_impl

return poll_impl.PollProactor

except ImportError:

try:

import epoll

import epoll_impl

return epoll_impl.EpollProactor

except ImportError:

try:

from select import epoll

import stdlib_epoll_impl

return stdlib_epoll_impl.StdlibEpollProactor

except ImportError:

try:

import kqueue

if kqueue.PYKQ_VERSION.split('.')[0] != '2':

raise ImportError("%s too old."%kqueue.PYKQ_VERSION)

import kqueue_impl

return kqueue_impl.KQueueProactor

except ImportError:

try:

from select import kqueue

import stdlib_kqueue_impl

return stdlib_kqueue_impl.StdlibKQueueProactor

except ImportError:

try:

import win32file

if not hasattr(win32file, 'ConnectEx'):

import warnings

warnings.warn("IOCPProactor implementation requires a newer pywin32 module.")

return

import pywintypes

import socket

import ctypes

import struct

import iocp_impl

return iocp_impl.IOCPProactor

except ImportError:

try:

import ctypes

import ctypes_iocp_impl

return ctypes_iocp_impl.CTYPES_IOCPProactor

except ImportError:

"Returns the first result that evaluates to true from a list of callables."

for imp in imps:

proactor = imp()

if proactor: