title: Round off and round down the time
body: <p>I am new to python and i need to figure out a solution in python that can round off a time > 30 minutes to 'next minute and 00 seconds' and time &lt; 30 minutes to 'previous minute and 00 seconds'. I tried several approaches like converting time in minutes to timedelta type and subtracting it from another variable containing same minutes but it didn't work. 
  I also applied some of the techniques mentioned in some other relevant questions but it didn't work. The time is already converted to datetime format through pd.to_datetime command.</p>
  
  <p>Here is a sample data:</p>
  
  <pre><code>df name: Order_data  
  column_name: Only_time
  
  11:10:40  
  09:13:26  
  21:29:50  
  19:13:37  
  21:09:15  
  19:51:43  
  08:55:57  
  13:31:01  
  18:21:16
  </code></pre>