Remove argument unpacking from get_areas

Making it only callable in one way is just less stuff to understand.

app/broadcast_areas/models.py

@@ -227,18 +227,11 @@ class BroadcastAreaLibraries(SerialisedModelCollection, GetItemByIdMixin):
     def __init__(self):
         self.items = BroadcastAreasRepository().get_libraries()
 
-    def get_areas(self, *area_ids):
-        # allow people to call `get_areas('a', 'b') or get_areas(['a', 'b'])`
-        if len(area_ids) == 1 and isinstance(area_ids[0], list):
-            area_ids = area_ids[0]
-
+    def get_areas(self, area_ids):
         areas = BroadcastAreasRepository().get_areas(area_ids)
         return [BroadcastArea(area) for area in areas]
 
-    def get_areas_with_simple_polygons(self, *area_ids):
-        if len(area_ids) == 1 and isinstance(area_ids[0], list):
-            area_ids = area_ids[0]
-
+    def get_areas_with_simple_polygons(self, area_ids):
         areas = BroadcastAreasRepository().get_areas_with_simple_polygons(area_ids)
         return [BroadcastArea.from_row_with_simple_polygons(area) for area in areas]
 

app/main/views/broadcast.py

@@ -287,7 +287,7 @@ def choose_broadcast_sub_area(service_id, broadcast_message_id, library_slug, ar
         broadcast_message_id,
         service_id=current_service.id,
     )
-    area = BroadcastMessage.libraries.get_areas(area_slug)[0]
+    area = BroadcastMessage.libraries.get_areas([area_slug])[0]
 
     back_link = _get_broadcast_sub_area_back_link(service_id, broadcast_message_id, library_slug)
 

app/models/broadcast_message.py

@@ -18,9 +18,9 @@ from app.notify_client.broadcast_message_api_client import (
     broadcast_message_api_client,
 )
 
-ESTIMATED_AREA_OF_LARGEST_UK_COUNTY = broadcast_area_libraries.get_areas(
+ESTIMATED_AREA_OF_LARGEST_UK_COUNTY = broadcast_area_libraries.get_areas([
     'ctyua19-E10000023'  # North Yorkshire
-)[0].polygons.estimated_area
+])[0].polygons.estimated_area
 
 
 class BroadcastMessage(JSONModel):
@@ -203,7 +203,7 @@ class BroadcastMessage(JSONModel):
 
     def get_areas(self, areas):
         return broadcast_area_libraries.get_areas(
-            *areas
+            areas
         )
 
     def get_simple_polygons(self, areas):