Rss problem with davidjeddy\RssFeed\RssReader

I set up davidjeddy\RssFeed\RssReader at my project with composer,I see the code at vendor folder but there is the error at my view Class ‘davidjeddy\RssFeed\RssReader’ not found.
I follow the instructions from here
this is the code,What is wrong?

echo davidjeddy\RssFeed\RssReader::widget([
‘channel’ => ‘’,
‘itemView’ => ‘item’,
‘pageSize’ => 5,
‘wrapClass’ => ‘rss-wrap’,
‘wrapTag’ => ‘div’,

Maybe the app can not load this class,What may be wrong.
I used this code