title: How Do i compare Two model fields against each other in django?
body: <p>I have this Model in my Models.py file.I want to to compare "start_date" and "end_date" so that start_date value would never be greater then end_date or vice-versa.How do i do this validation?</p>
  
  <pre><code>class Completion(models.Model):
  
      start_date = models.DateField()
      end_date = models.DateField()
      batch = models.ForeignKey(Batch)
      topic = models.ForeignKey(Topic)
  </code></pre>