title: Can I get duration of the videos from YouTuve API3.0 even if it's search result?
body: <p>I know it can get duration if fetch particular video directly.<br>
  What if it's search result?  </p>
  
  <p>I'm pretty sure that it provides us video's title, unique ID, and published date.  </p>
  
  <p>In my code below, any error won't occur unless I put <strong>contentDetails</strong> into 4th line.  </p>
  
  <p>It seems that the error occurs when there are more than two in part section.<br>
  If I leave it just as <strong>:part => 'snippet',</strong>, everything works fine.<br>
  However I have to add contentDetails to gain information about duration of the videos on Youtube. </p>
  
  <p>How can I achieve it?</p>
  
  <p><strong>videos_controller.rb</strong></p>
  
  <pre><code>@search_response = client.execute!(
    :api_method =&gt; youtube.search.list,
    :parameters =&gt; {
      :part =&gt; 'snippet, contentDetails',
      :q =&gt; 'cats',
      :maxResults =&gt; 20,
      :order =&gt; 'date',
      :pageToken =&gt; pageToken
    }
  )
  </code></pre>
  
  <p><strong>Error</strong></p>
  
  <pre><code>ActionView::Template::Error (undefined method `prev_page_token' for nil:NilClass):
      1: 
      2: &lt;% if !@search_response.prev_page_token.nil? %&gt;
  </code></pre>