Delete second row of header in PANDAS
<p>I have a dataframe in PANDAS which has two lines of headers.How could I remove the second line? For example, I have the following:</p>

<pre><code>         AA  BB  CC  DD
         A   B   C   D
Index    
   1     1   2   3   4
   2     5   6   7   8
   3     9   1   2   3
</code></pre>

<p>and I would like to get something like this:</p>

<pre><code>         AA  BB  CC  DD
Index    
   1     1   2   3   4
   2     5   6   7   8
   3     9   1   2   3
</code></pre>

<p>Thank you very much.</p>