title: dropping empty columns in pandas 0.23+
body: <p>In earlier versions of pandas, you could drop empty columns simply with:</p>
  
  <pre><code>df.dropna(axis='columns')
  </code></pre>
  
  <p>However, dropna has been depreciated in later builds. How would one now drop multiple (without specifically indexing) empty columns from a dataframe?</p>