human
Solve the following python programming problem given the following code:
@ classmethod 
@ gen.coroutine 
def NotifyRegisterUser(cls, client, user_dict, ident_dict, timestamp, is_first_register, is_linking) : 
    'Notifies friends and contact owners of the user when one (or several) of the following
    have occurred:

    1. One or more friend-visible user attributes have been updated (such as name).

    2. The user is registering for the first time (i.e. was a prospective user before). In this
       case, "is_first_register" is true.

    3. A new identity has been linked to the user. In this case, "is_linking" is true.

    The user himself is notified since a user always has a friend relationship with himself.
    ' 
    from viewfinder.backend.op.alert_manager import AlertManager 
    if (is_first_register or is_linking) : 
        name = ('first register contact' if is_first_register else 'link contact') 
        (yield NotificationManager._NotifyUsersWithContact (client, name, ident_dict ['key'], timestamp)) 
if any (((attr_name != 'user_id') for attr_name in user_dict.keys ())) : 
        invalidate = { 
            'users' : [user_dict ['user_id']], 
} 
        (yield NotificationManager._NotifyFriends (client, 'register friend', user_dict ['user_id'], is_first_register)) 
else : 
        if (is_first_register or is_linking) : 
            (yield NotificationManager._NotifyUserInvalidateSelf (client, 'register friend self', user_dict ['user_id'])) 
if is_first_register : 
        @ gen.coroutine 
        def _VisitContactUserId(contact_user_id) : 
            settings = (yield gen.Task (AccountSettings.QueryByUser, client, contact_user_id, None)) 
            (yield AlertManager.SendRegisterAlert (client, user_dict ['user_id'], contact_user_id, settings)) 
(yield gen.Task (Contact.VisitContactUserIds, client, ident_dict ['key'], _VisitContactUserId)) 

    
    

    Fix the buggy line: (yield NotificationManager._NotifyFriends (client, 'register friend', user_dict ['user_id'], is_first_register))
assistant
#Here is Python program to fix the buggy line: (yield NotificationManager.

(yield NotificationManager._NotifyFriends (client, 'register friend', user_dict ['user_id'], invalidate))