title: How to add/subtract time (hours, minutes, etc.) from a Pandas DataFrame.Index whos objects are of type datetime.time?
body: <p>I've got a DataFrame who's index is just datetime.time and there's no method in  DataFrame.Index and datetime.time to shift the time. datetime.time has replace but that'll only work on individual items of the Series? </p>
  
  <p>Here's an example of the index used:</p>
  
  <pre><code>In[526]:  dfa.index[:5]
  Out[526]: Index([21:12:19, 21:12:20, 21:12:21, 21:12:21, 21:12:22], dtype='object')
  
  In[527]:  type(dfa.index[0])
  Out[527]: datetime.time
  </code></pre>