title: create pivot table with multilevel index in pandas
body: <p>Dataframe is setup like so. I want a pivot table with a multi-level index of account, pseudo. I want the columns to be the individual weeks, and the values to be sales. The data is pseudo x week x account so I shouldn't need to aggregate any data. How can I accomplish?</p>
  
  <pre><code>   pseudo        week     account   sales
  0   31527  2017-12-30  4430012511    2.79
  1  145584  2017-12-16  4430012511    8.37
  2   31608  2017-12-23  4430012511   19.53
  3    6362  2017-12-16  4430012511    5.58
  </code></pre>