title: Passing a string variable to rename function pandas
body: <p>I'm trying to rename a single column in a DataFrame by passing in a string variable to rename function and getting the below error, any help is much appreciated.</p>
  <pre class="lang-py prettyprint-override"><code>import pandas as pd
  
  new = &quot;new_name&quot;
  
  df.rename(index=str, columns={&quot;old_name&quot;: new})
  </code></pre>
  <p>The error:</p>
  <pre><code>TypeError: 'set' object is not callable
  </code></pre>