diff --git a/shiftregister/app/models.py b/shiftregister/app/models.py
index c2452b9..4fead8f 100644
--- a/shiftregister/app/models.py
+++ b/shiftregister/app/models.py
@@ -21,10 +21,12 @@ class Shift(models.Model):
     # todo: add helper amount override field
     def __str__(self):
         return f"{self.room.name}: {self.start_at}"
+
     def has_ended(self):
         return (self.start_at + self.duration) < timezone.now()
+
     def is_running(self):
-        return  (self.start_at <=timezone.now()) and (not self.has_ended())
+        return (self.start_at <= timezone.now()) and (not self.has_ended())
 
 
 class Helper(models.Model):
@@ -43,19 +45,24 @@ class Helper(models.Model):
         msg = Message(to=self, text=text)
         msg.save()
         return token
-    
+
     # current or next shift
     def important_shift(self):
-        ret = ShiftRegistration.objects.annotate(
+        ret = (
+            ShiftRegistration.objects.annotate(
                 shift_end=ExpressionWrapper(
                     F("shift__start_at") + F("shift__duration"),
                     output_field=models.DateTimeField(),
-                )).filter(helper=self, shift_end__gte=timezone.now()).order_by("shift__start_at").first()
+                )
+            )
+            .filter(helper=self, shift_end__gte=timezone.now())
+            .order_by("shift__start_at")
+            .first()
+        )
         if ret:
             return ret.shift
 
 
-
 class ShiftRegistration(models.Model):
     class Meta:
         unique_together = (("shift", "helper"),)