title: Pandas: change multilevel column name for one particular column
body: <p>I have a dataframe like this:</p>
  
  <pre><code>type      A                           B
  kind      A1                          B1
  name      alpha  aplpha1  alpha_dog   beta beta1 alpha_dog
  timestamp
  20180101  1      2        3           4     5    6
  20180102  ...
  20180103  ...
  </code></pre>
  
  <p>I want to change the <code>kind</code> of the <code>alpha_dog</code> columns, so I can have the following:</p>
  
  <pre><code>type      A                           B
  kind      A1              google      B1         google
  name      alpha  aplpha1  alpha_dog   beta beta1 alpha_dog
  timestamp
  20180101  1      2        3           4     5    6
  20180102  ...
  20180103  ...
  </code></pre>
  
  <p>I have looked at <code>df.rename/multiindex.rename</code> and none of them works for this cases and I found it really hard to do this operation, what's your opinion? Is there an easy option I can take?</p>