title: Check if Date is in Daylight Savings Time for Timezone Without pytz
body: <p>For certain reasons, my employer does not want to use pip to install third party packages and wants me to use packages only hosted on trusty. Thus, I now cannot use pytz in my code. How would I go about checking if a certain date in a timezone is in DST? Here's my original code using pytz.</p>
  
  <pre><code>    import pytz
      import datetime
      ...
  
      target_date = datetime.datetime.strptime(arg_date, "%Y-%m-%d")
      time_zone = pytz.timezone('US/Eastern')
      dst_date = time_zone.localize(target_date, is_dst=None)
      est_hour = 24
      if bool(dst_date.dst()) is True:
          est_hour -= 4
      else:
          est_hour -= 5
  </code></pre>