title: How to access row data in before_save_instance for Django Import Export
body: <p>I'm trying to use <a href="http://django-import-export.readthedocs.io/en/latest/index.html" rel="nofollow noreferrer">django-import-export</a> to load data into my Django site admin interface.</p>
  
  <p>During the input I want to do some complicated data validation which involves creating and/or modifying other models related to the one being uploaded into with django-import-export.</p>
  
  <p>It seems like the <code>before_save_instance</code> hook is the time in the <a href="http://django-import-export.readthedocs.io/en/latest/import_workflow.html" rel="nofollow noreferrer">import workflow</a> that I want to perform this complicated validation.</p>
  
  <p><code>before_save_instance</code>'s input parameters include only the object for the model being updated, which does not contain all the data from the row being imported.</p>
  
  <p>In particular I don't see the read only fields from the row being imported anywhere (and I need them for my validation logic).</p>
  
  <p>How can I get access to the entire row being imported from inside of <code>before_save_instance</code>?</p>