Creating choose folder-dialog from Python using Windows API

I'm trying to create a choose folder-dialog from Python, but I'm having problems setting the initial folder path for the dialog. I think it's a problem converting the string to a LPARAM when I'm setting the _BROWSEINFO structure.

bi.lParam = cast(path.encode("ascii", "ignore"), POINTER(LPARAM)).contents

I'm getting this error in the callback:

windll.user32.SendMessageA(handle, _BFFM_SETSELECTIONA, 1, lpdata)
ctypes.ArgumentError: argument 4: <class 'OverflowError'>: int too long to convert

Below is the code I'm using, it seems to work well except the call to SendMessageA.

I'm setting the _BROWSEINFO structure in browse_folder,

_WM_USER = 0x400
_BFFM_INITIALIZED = 1
_BFFM_SETSELECTIONA = _WM_USER + 102
_BFFM_SETSELECTIONW = _WM_USER + 103
_BIF_RETURNONLYFSDIRS = 0x00000001
_BIF_NEWDIALOGSTYLE = 0x00000040
_BFFCALLBACK = WINFUNCTYPE(None, HWND, UINT, LPARAM, LPARAM)

def _browse_callback(handle, umsg, lparam, lpdata):
    if(umsg == _BFFM_INITIALIZED):
        if(lpdata is not None):
            windll.user32.SendMessageA(handle, _BFFM_SETSELECTIONA, 1, lpdata)
    return 0

class _SHITEMID(Structure):
    _fields_ = [
                ("cb", USHORT),
                ("abID", BYTE)]

class _ITEMIDLIST(Structure):
    _fields_ = [
                ("mkid", POINTER(_SHITEMID))]

class _BROWSEINFO(Structure):
    _fields_ = [
                ("hwndOwner", HWND),
                ("pidlRoot", UINT),
                ("pszDisplayName", LPCSTR),
                ("lpszTitle", LPCSTR),
                ("ulFlags", UINT),
                ("lpfn", _BFFCALLBACK),
                ("lParam", LPARAM),
                ("iImage", INT)]

def browse_folder(path, message):
    display_name = create_string_buffer(MAX_PATH)
    end_path = create_string_buffer(MAX_PATH)

    pidl_root =  _ITEMIDLIST()

    bi = _BROWSEINFO()
    bi.hwndOwner = 0
    bi.pidlRoot = 0
    bi.pszDisplayName = addressof(display_name)
    bi.lpszTitle = message.encode("ascii", "ignore")
    bi.ulFlags = _BIF_RETURNONLYFSDIRS | _BIF_NEWDIALOGSTYLE
    bi.lpfn = _BFFCALLBACK(_browse_callback)
    bi.lParam = cast(path.encode("ascii", "ignore"), POINTER(LPARAM)).contents
    bi.iImage = 0

    pidl = windll.shell32.SHBrowseForFolder(addressof(bi))
    print(display_name.value)
    windll.shell32.SHGetPathFromIDList(pidl, addressof(end_path))
    print(repr(end_path.value))