FBSDK在Swift

Question

我在翻译这段Objective-C代码时遇到了困难：

- (void)_accessTokenChanged:(NSNotification *)notification
{
FBSDKAccessToken *token = notification.userInfo[FBSDKAccessTokenChangeNewKey];

if (!token) {
[self _deselectRow];
} else {
SUProfileTableViewCell *cell = (SUProfileTableViewCell *)[self.tableView cellForRowAtIndexPath:_currentIndexPath];
cell.accessoryType = UITableViewCellAccessoryCheckmark;
NSInteger slot = [self _userSlotFromIndexPath:_currentIndexPath];
SUCacheItem *item = [SUCache itemForSlot:slot] ?: [[SUCacheItem alloc] init];
if (![item.token isEqualToAccessToken:token]) {
item.token = token;
[SUCache saveItem:item slot:slot];
cell.userID = token.userID;
}
}
}

分为：

func accessTokenChanged(notification: NSNotification) -> Void {
    var token: AnyObject? = notification.userInfo![FBSDKAccessTokenChangeNewKey] as! FBSDKAccessToken

    if (token == nil) {
        self.deselectRow()
    } else {
        let cell = self.usersTable.cellForRowAtIndexPath(currentIndexPath!) as! FBUserCell
        cell.accessoryType = UITableViewCellAccessoryType.Checkmark
        var slot: Int = self.userSlotFromIndexPath(currentIndexPath!)
        var item: CacheItem = Cache.itemForSlot(slot)!

        if (item.token.isEqualToAccessToken(token) == false) {
            item.token = token
            Cache.saveItem(item, slot: slot)
            cell.userIDLabel = token?.userID
        }
    }

}

我在if语句中收到两个令牌的错误：找不到＆＃39; ==＆＃39;接受提供的参数。如果我在＆＃34; item＆＃34;之前加上感叹号，我会得到同样的错误。在if语句中，然后用＆＃39;！＆＃39;明显。

我做错了什么？

谢谢！