为什么我的 SetWindowsHookEx 不可以成功获取键盘事件？

代码如下
我的平台是 Windows10
为什么这样写不可以获取键盘事件？
你们有其他截获键盘事件的方法吗？

# coding=utf-8
from ctypes import *
from ctypes import wintypes
import win32con

SetWindowsHookEx=windll.user32.SetWindowsHookExA
UnhookWindowsHookEx=windll.user32.UnhookWindowsHookEx
CallNextHookEx=windll.user32.CallNextHookEx
GetMessage=windll.user32.GetMessageA
GetModuleHandle=windll.kernel32.GetModuleHandleW
#保存键盘钩子函数句柄
keyboard_hd = None


class KBDLLHOOKSTRUCT(Structure):
    _fields_ = [
        ('vkCode',c_int),
        ('scanCode', c_int),
        ('flags', c_int),
        ('time', c_int),
        ('dwExtraInfo', c_uint),
        ('',c_void_p)
    ]

def wait_for_msg():
    msg = wintypes.MSG()
    GetMessage(msg, 0, 0, 0)


def keyboard_pro(nCode, wParam, lParam):
    """
    函数功能：键盘钩子函数，当有按键按下时此函数被回调
    """
    if nCode == win32con.HC_ACTION:
        KBDLLHOOKSTRUCT_p = POINTER(KBDLLHOOKSTRUCT)
        param=cast(lParam,KBDLLHOOKSTRUCT_p)
        print(param.contents.vkCode)
    # return CallNextHookEx(keyboard_hd, nCode, wParam, lParam)
    # 屏蔽事件
    return None


def start_keyboard_hook():
    """
    函数功能：启动键盘监听
    """
    HOOKPROTYPE = CFUNCTYPE(c_int, c_int, c_int, POINTER(c_void_p))
    pointer = HOOKPROTYPE(keyboard_pro)
    keyboard_hd = SetWindowsHookEx(
        win32con.WH_KEYBOARD_LL,
        pointer,
        GetModuleHandle(None),
        0)
    wait_for_msg()


def stop_keyboard_hook():
    """
    函数功能：停止键盘监听
    """
    UnhookWindowsHookEx(keyboard_hd)


start_keyboard_hook()

(python3 似乎不能用 pyHook)