title: Detect whether a dataframe has a MultiIndex
body: <p>I am building a new method to parse a <code>DataFrame</code> into a Vincent-compatible format. This requires a standard <code>Index</code> (Vincent can't parse a <code>MultiIndex</code>).</p>
  
  <p>Is there a way to detect whether a Pandas <code>DataFrame</code> has a <code>MultiIndex</code>?</p>
  
  <pre><code>In: type(frame)
  Out: pandas.core.index.MultiIndex
  </code></pre>
  
  <p>I've tried:</p>
  
  <pre><code>In: if type(result.index) is 'pandas.core.index.MultiIndex':
          print True
      else:
          print False
  Out: False
  </code></pre>
  
  <p>If I try without quotations I get:</p>
  
  <pre><code>NameError: name 'pandas' is not defined
  </code></pre>
  
  <p>Any help appreciated.</p>
  
  <p>(Once I have the <code>MultiIndex</code>, I'm then resetting the index and merging the two columns into a single string value for the presentation stage.)</p>