title: Python FutureWarning: Indexing with multiple keys (implicitly converted to a tuple of keys)
body: <p>I've recently upgraded Python to 3.7.6 and my existing code: </p>
  
  <pre><code>df['Simple_Avg_Return'] = df.groupby(['YF_Ticker'])['Share_Price_Delta_Percent', 'Dividend_Percent'].transform(
          sum).divide(2).round(2) 
  </code></pre>
  
  <p>Is now throwing this warning:</p>
  
  <pre><code>FutureWarning: Indexing with multiple keys (implicitly converted to a
  tuple of keys) will be deprecated, use a list instead.  
  </code></pre>
  
  <p>How would I go about converting this to a list as advised and where?</p>