title: Understanding what is/ how to use prior.scale in Prophet?
body: <p>I'm reviewing Prophet's documentation on the <code>add_regressors</code> method and came across something called a <code>prior.scale</code>, which is explained as <code>Float scale for the normal prior. If not provided, holidays.prior.scale will be used.</code>. </p>
  
  <p>I'm looking for information on what this is/ how it effects predictions, and how to assess/tune the values that it is set to.</p>