title: Rolling mean with customized window with Pandas
body: <p>Is there a way to customize the window of the rolling_mean function? </p>
  
  <pre><code>data
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  </code></pre>
  
  <p>Let's say the window is set to 2, that is to calculate the average of 2 datapoints before and after the obervation including the observation. Say the 3rd observation. In this case, we will have <code>(1+2+3+4+5)/5 = 3</code>. So on and so forth.</p>