fix style with flake8 in new test model def

Author: marcanuy

simple_history/tests/models.py

@@ -482,15 +482,18 @@ class InheritTracking3(BaseInheritTracking3):
 class InheritTracking4(TrackedAbstractBaseA):
     pass
 
+
 class BasePlace(models.Model):
     name = models.CharField(max_length=50)
     history = HistoricalRecords(
         inherit=True,
-    ) 
+    )
+
 
 class InheritedRestaurant(BasePlace):
     serves_hot_dogs = models.BooleanField(default=False)
 
+
 class BucketMember(models.Model):
     name = models.CharField(max_length=30)
     user = models.OneToOneField(