How to make User logout from twitter fabric ios

I have made a basic app using Twitter's fabric that allows user to tweet within my app and Provide Login With Twitter.Every things works a I Wanted.

How my app Works

If the user doesn't logged in to twitter my app allows him to login and if he is login then directly allows him to tweet.

Now the Big Part Comes

As I saw in many Apps I Can Remove my signed account from the app.And I am not able to get any method that help me to achieve this. I want to allow user to logout from twitter within my app whenever he/She wants.

I googled but i doesn't find anything

Here Is my Code:

- (IBAction)LogOut:(id)sender
{
    [[Twitter sharedInstance]logOut];
}

- (IBAction)LogMeIn:(id)sender
{
[[Twitter sharedInstance] logInWithCompletion:^
 (TWTRSession *session, NSError *error) {
     if (session) {
         NSLog(@"signed in as %@", [session userName]);
         [LoginButton setTitle:@"LogOut" forState:normal];

     } else {
         NSLog(@"error: %@", [error localizedDescription]);
     }
 }];
}

Solution

UPDATE: May 2016 - Framework has changed so this answer is no longer relevant.

See this answer: https://stackoverflow.com/a/35765833/940709 and this answer: https://stackoverflow.com/a/30916904/940709 instead.

[[[Twitter sharedInstance] sessionStore] logOutUserID:USERID];