Minor syntax simplification

inventory.py

@@ -210,15 +210,13 @@ class TimedDrop(BaseDrop):
 
     @property
     def total_remaining_minutes(self) -> int:
-        return (
+        return sum(
-            sum(
             (
                 self.campaign.timed_drops[pid].remaining_minutes
                 for pid in self._all_preconditions
             ),
             start=self.remaining_minutes,
         )
-        )
 
     @cached_property
     def progress(self) -> float: