title: When to use getActiveSpreadsheet?
body: <p>I'm trying to understand when to use <code>getActiveSpreadsheet()</code>. </p>
  
  <p>I've seen numerous examples:</p>
  
  <pre><code>var ss = SpreadsheetApp.getActiveSheet();
  </code></pre>
  
  <p>But I've also seen:</p>
  
  <pre><code>var ss = SpreadsheetApp.getActiveSpreadsheet().getActiveSheet();
  </code></pre>
  
  <p>Is the active spreadsheet implied in some circumstances?</p>