title: getting random 404 errors using Valence
body: <p>When I make API calls to the server, I'm getting 404 errors for various data -- grades, role IDs, terms -- that I won't get on the next time I call it.  The data's there on the server, viewable by the same user, and is often returned successfully, but not every time.  The same user context will return data successfully for other calls.</p>
  
  <p>Any ideas what could be causing this?</p>
  
  <p>I'm using the Valence API with the Python client library and our 9.4.1 SP18 instance of Desire2Learn in a non-interactive script.</p>
  
  <p>more detail:  the text it returns on the bad 404s is " ErrorThe system cannot find the path specified."</p>