title: pandas: rename axis in df
body: <p>I have a df which looks like this:</p>
  
  <pre><code>                Column 1
  Channel          
  Apples            1.0
  Oranges           2.0
  Puppies           3.0
  Ducks             4.0
  </code></pre>
  
  <p>I would like to rename the axis so it looks like this:</p>
  
  <pre><code>Channel         Column 1          
  Apples            1.0
  Oranges           2.0
  Puppies           3.0
  Ducks             4.0
  </code></pre>
  
  <p>I tried these but got the same error msg:</p>
  
  <pre><code>merged_df.rename_axis("Channel")
  merged_df.rename_axis("Channel", axis='columns')
  
  TypeError: 'str' object is not callable
  </code></pre>