android开发：融云怎么清除指定会话列表、所有会话列表

场景：比如说A和B是好友，A删除B后应该删除聊天item,代码如下

/**
     * 删除聊天item的方法
     * 设备解绑的时候调用，删除聊天列表的item
     *
     * @param userPhoneNumber 用户手机号码
     */
    @Override
    public void removeRongIMMessage(String userPhoneNumber) {
        RongIM.getInstance().removeConversation(Conversation.ConversationType.PRIVATE, userPhoneNumber, new RongIMClient.ResultCallback<Boolean>() {
            @Override
            public void onSuccess(Boolean aBoolean) {
                LogUtil.e("删除成功");
                RongIM.getInstance().addUnReadMessageCountChangedObserver(observer, Conversation.ConversationType.PRIVATE);
                RongIM.getInstance().removeUnReadMessageCountChangedObserver(observer);
            }
            @Override
            public void onError(RongIMClient.ErrorCode errorCode) {
                LogUtil.e("删除失败");
            }
        });
    }

    /**
     * 删除所有聊天item的方法
     */
    @Override
    public void removeRongIMAllMessage() {
        RongIM.getInstance().clearConversations(new RongIMClient.ResultCallback() {
            @Override
            public void onSuccess(Object o) {
                LogUtil.e("删除成功");
                RongIM.getInstance().addUnReadMessageCountChangedObserver(observer, Conversation.ConversationType.PRIVATE);
                RongIM.getInstance().removeUnReadMessageCountChangedObserver(observer);
            }
            @Override
            public void onError(RongIMClient.ErrorCode errorCode) {

            }
        }, Conversation.ConversationType.PRIVATE);
    }