title: convert timestamp to datetime.datetime in pandas.Series
body: <p>I have pandas Series where index is a list of integer (timestamp), how can I convert them to datetime.datetime (with timezone) more efficient than below raw conversion? </p>
  
  <pre><code>pd.Series(data=s.values, index=map(lambda x:datetime.datetime.fromtimestamp(x,tz=utc), s.index))
  </code></pre>