title: Pandas: Adding TimeZone offset to the timestamp after using tz_convert
body: <p>I have the following dataframe, with some offset time. </p>
  
  <pre><code>      feed_id                created_at
  7191  1009408 2019-03-10 01:55:35-05:00
  7192  1009408 2019-03-10 01:56:35-05:00
  7193  1009408 2019-03-10 01:57:36-05:00
  7194  1009408 2019-03-10 01:58:38-05:00
  7195  1009408 2019-03-10 01:59:38-05:00
  7196  1009408 2019-03-10 03:00:39-04:00
  7197  1009408 2019-03-10 03:01:40-04:00
  7198  1009408 2019-03-10 03:02:41-04:00
  7199  1009408 2019-03-10 03:03:42-04:00
  </code></pre>
  
  <p>I got here by using: </p>
  
  <pre><code>mydf['created_at']=mydf['created_at'].dt.tz_localize('UTC').dt.tz_convert('America/Montreal')
  </code></pre>
  
  <p>I want the offset time to be added to the timestamp, if a date looks like 2019-03-10 01:55:35-05:00, I want it to look like 2019-03-09 20:55:35. </p>
  
  <p>I saw a suggestion on <a href="https://stackoverflow.com/questions/47620882/adding-offset-to-timestamp-in-pandas">this post</a> that thought would help me but the offset being added is constant and I want to consider DST for this exercise. </p>
  
  <p>Is there a way to get an "timezone-aware" timedelta or offset that takes DST into consideration?</p>
  
  <p>Or is there a simpler way to achieve this?</p>