title: Check if a polygon is a multipolygon in Shapely
body: <p>How can I check if a polygon entity is actually a multipolygon?
  I've tried: </p>
  
  <pre><code>if len(polygon) &gt; 1:
  </code></pre>
  
  <p>but then get the error:</p>
  
  <pre><code>TypeError: object of type 'Polygon' has no len()
  </code></pre>
  
  <p>I've tried <code>Nill</code>, <code>None</code> and others, nothing worked.</p>