title: pandas - remove duplicated rows in a MultiIndex DataFrame
body: <p>I need to remove duplicated rows with the same multi-index from a <code>df</code>.</p>
  <p>The multi-index are [latitude, longitude, AET_date].</p>
  <pre><code>                                                                    FFDI_daily_max
  latitude                    longitude                   AET_date    
  -39.20000076293945312500    140.80000305175781250000    1972-01-20  1.20000004768371582031  
                                                          1972-01-21  0.89999997615814208984
                                                          **1972-01-22**  1.50000000000000000000
                                                          **1972-01-22**  1.40000000000000000000
                                                          1972-01-23  1.80000000000000000000
                                                          1972-01-24  1.40000000000000000000
  ... ... ... ...
  -33.90000152587890625000    150.00000000000000000000    1972-01-20  1.10000004768371582031  
                                                          1972-01-21  0.49999997615814208984
                                                          **1972-01-22**  1.20000000000000000000
                                                          **1972-01-22**  1.10000000000000000000
                                                          1972-01-23  1.60000000000000000000
                                                          1972-01-24  1.60000000000000000000
  </code></pre>
  <p>There are duplicated rows in AET_Date for each (latitude and longitude). What I want to achieve is to remove the duplicated row and keep the row with the higher FFDI_daily_max.</p>