title: In pandas dataframe keep repeated values that are only in a group, if value is repeated after other value then print some message
body: <p>Example Dataframe:</p>
  <pre><code>A1
  A1
  A1 #these values are ok because these are repeated continuously
  A2
  A3
  A4
  A1 #this is duplicate value as this is not in continuation
  A5
  </code></pre>