我在同一页面的两个位置使用此脚本来输出一些RSS提要：

<?php
    include_once(ABSPATH . WPINC . \'/feed.php\');
    $rss = fetch_feed(\'https://api.twitter.com/1/statuses/user_timeline.rss?screen_name=BarackObama\');
    $maxitems = $rss->get_item_quantity(3);
    $rss_items = $rss->get_items(0, $maxitems);
?>
<?php if ($maxitems == 0) echo \'<p class="alert">No activity to display.</p>\'; ?>
<ul>
<?php
    if (!$maxitems == 0)
    foreach ( $rss_items as $item ) : ?>
        <li>
            <a href="<?php echo $item->get_permalink(); ?>">
                <?php echo $item->get_title(); ?>
                <time datetime="<?php echo $item->get_local_date(\'%Y-%m-%d %H:%M\'); ?>" class="timestamp">
                    <?php echo $item->get_local_date(\'%A %d %b %H:%M\'); ?>
                </time>
            </a>
        </li>
    <?php endforeach; ?>
</ul>

我正在手动设置functions.php 至两小时：

function filter_handler( $seconds ) {
    return 7200;
}
add_filter( \'wp_feed_cache_transient_lifetime\', \'filter_handler\' );

每天有几次，提要会中断并显示此错误：

Fatal error: Call to undefined method WP_Error::get_item_quantity() in /public_html/wp-content/themes/twentyeleven/home-page.php on line 100

WordPress获取这个推特提要似乎偶尔会失败，然后错误会输出2个小时，直到刷新缓存。

我怎么才能避开这个？

// functions.php
function fetch_twitter()
{
    $rss = fetch_feed(\'https://api.twitter.com/1/statuses/user_timeline.rss?screen_name=BarackObama\');

    if ( is_wp_error( $rss ) )
        return;

    // continue in your function
    $maxitems = $rss->get_item_quantity(3);
}

// template
fetch_twitter();