title: Python win32gui.PostMessage can't work
body: <p>I want to close the window which I found , here is the code ..</p>
  
  <pre><code>import ctypes
  import win32gui, win32con, win32api
  
  EnumWindows = ctypes.windll.user32.EnumWindows
  EnumWindowsProc = ctypes.WINFUNCTYPE(ctypes.c_bool, ctypes.POINTER(ctypes.c_int), ctypes.POINTER(ctypes.c_int))
  GetWindowText = ctypes.windll.user32.GetWindowTextW
  GetWindowTextLength = ctypes.windll.user32.GetWindowTextLengthW
  IsWindowVisible = ctypes.windll.user32.IsWindowVisible
  
  titles = []
  user32 = ctypes.windll.user32
  ole32 = ctypes.windll.ole32
  
  def foreach_window(hwnd, lParam):
      if IsWindowVisible(hwnd):
          length = GetWindowTextLength(hwnd)
          buff = ctypes.create_unicode_buffer(length + 1)
          GetWindowText(hwnd, buff, length + 1)
          titles.append(buff.value)
          if (buff.value == '123.txt'):
              print('I got u...')
              win32gui.PostMessage(hwnd,  win32con.WM_CLOSE,  0,  0)
      return True
  
  EnumWindows(EnumWindowsProc(foreach_window), 0)
  </code></pre>
  
  <p>but the error occur ,</p>
  
  <pre><code>win32gui.PostMessage(hwnd,  win32con.WM_CLOSE,  0,  0)
  TypeError: The object is not a PyHANDLE object
  </code></pre>
  
  <p>how can I solve it ?
  thanks</p>