      def __str__(self):
          return "%s" % self.time
  
  
  @python_2_unicode_compatible
  class SimulationRun(models.Model):
      start = models.ForeignKey(Time, models.CASCADE, null=True, related_name='+')
      end = models.ForeignKey(Time, models.CASCADE, null=True, related_name='+')
      midpoint = models.TimeField()
  
 
</s> remove @python_2_unicode_compatible
 </s> add  </s> remove @python_2_unicode_compatible
 </s> add  </s> remove @python_2_unicode_compatible
 </s> add  </s> remove @python_2_unicode_compatible
 </s> add  </s> remove @python_2_unicode_compatible
 </s> add 
      def __str__(self):
          return "%s" % self.time
  
  

  class SimulationRun(models.Model):
      start = models.ForeignKey(Time, models.CASCADE, null=True, related_name='+')
      end = models.ForeignKey(Time, models.CASCADE, null=True, related_name='+')
      midpoint = models.TimeField()
  
keep keep keep keep replace keep keep keep keep keep
 Refs #23919 -- Removed python_2_unicode_compatible decorator usage 
tests/expressions/models.py