title: Pandas groupby multiple columns, list of multiple columns
body: <p>I have the following data:</p>
  
  <pre><code>Invoice NoStockCode Description                         Quantity    CustomerID  Country
  536365  85123A      WHITE HANGING HEART T-LIGHT HOLDER  6           17850       United Kingdom
  536365  71053       WHITE METAL LANTERN                 6           17850       United Kingdom
  536365  84406B      CREAM CUPID HEARTS COAT HANGER      8           17850       United Kingdom
  </code></pre>
  
  <p>I am trying to do a groupby so i have the following operation:</p>
  
  <pre><code>df.groupby(['InvoiceNo','CustomerID','Country'])['NoStockCode','Description','Quantity'].apply(list)
  </code></pre>
  
  <p>I want to get the output</p>
  
  <pre><code>|Invoice |CustomerID |Country        |NoStockCode              |Description                                                                                 |Quantity       
  |536365| |17850      |United Kingdom |85123A, 71053, 84406B    |WHITE HANGING HEART T-LIGHT HOLDER, WHITE METAL LANTERN, CREAM CUPID HEARTS COAT HANGER     |6, 6, 8            
  </code></pre>
  
  <p>Instead I get:</p>
  
  <pre><code>|Invoice |CustomerID |Country        |0         
  |536365| |17850      |United Kingdom |['NoStockCode','Description','Quantity']
  </code></pre>
  
  <p>I have tried agg and other methods, but I haven't been able to get all of the columns to join as a list. I don't need to use the list function, but in the end I want the different columns to be lists.</p>