Clean up convoy code.

game/game.py

@@ -34,7 +34,7 @@ from .settings import Settings
 from .theater import ConflictTheater, ControlPoint, TheaterGroundObject
 from game.theater.theatergroundobject import MissileSiteGroundObject
 from .threatzones import ThreatZones
-from .transfers import PendingTransfers, RoadTransferOrder
+from .transfers import Convoy, ConvoyMap, PendingTransfers, RoadTransferOrder
 from .unitmap import UnitMap
 from .weather import Conditions, TimeOfDay
 
@@ -122,7 +122,7 @@ class Game:
 
         self.aircraft_inventory = GlobalAircraftInventory(self.theater.controlpoints)
 
-        self._transfers = PendingTransfers()
+        self.transfers = PendingTransfers()
 
         self.sanitize_sides()
 
@@ -154,14 +154,6 @@ class Game:
         # Regenerate any state that was not persisted.
         self.on_load()
 
-    @property
-    def transfers(self) -> PendingTransfers:
-        try:
-            return self._transfers
-        except AttributeError:
-            self._transfers = PendingTransfers()
-            return self._transfers
-
     def generate_conditions(self) -> Conditions:
         return Conditions.generate(
             self.theater, self.current_day, self.current_turn_time_of_day, self.settings