title: Python subtract time
body: <p>I have a value from a database that I believe is in a string format "03:00:00". I want to indicate that this is a time value in python and then use it to set a range (ex. from 02:00:00 to 04:00:00)</p>
  
  <p>I've imported the datetime module, but any time I try and perform an operation on the time value, I receive an internal server error.</p>
  
  <pre><code>from datetime import date, time, timedelta
  
  time_limit = "03:00:00" ## this is actually received as a get response from JS
  
  time_upper_limit = time_limit + timedelta(minutes=60)
  </code></pre>
  
  <p>The code fails at time_upper_limit. Any idea why this is happening? Do I need to convert the time value?</p>