diff --git a/data-serving/reusable-data-service/reusable_data_service/controller/case_controller.py b/data-serving/reusable-data-service/reusable_data_service/controller/case_controller.py
index e4ed803b2..8dd4589b1 100644
--- a/data-serving/reusable-data-service/reusable_data_service/controller/case_controller.py
+++ b/data-serving/reusable-data-service/reusable_data_service/controller/case_controller.py
@@ -19,23 +19,20 @@ def get_case(self, id: str):
             return f"No case with ID {id}", 404
         return jsonify(case), 200
 
-    def list_cases(self, page:int=None, limit:int=None):
+    def list_cases(self, page: int = None, limit: int = None):
         """Implements get /cases."""
         page = 1 if page is None else page
         limit = 10 if limit is None else limit
         validation_error = None
         if page <= 0:
-            validation_error = { "message" : "page must be >0" }
+            validation_error = {"message": "page must be >0"}
         if limit <= 0:
-            validation_error = { "message" : "limit must be >0" }
+            validation_error = {"message": "limit must be >0"}
         if validation_error is not None:
             return jsonify(validation_error), 422
         cases = self.store.fetch_cases(page, limit)
         count = self.store.count_cases()
-        response = {
-            "cases": cases,
-            "total": count
-        }
+        response = {"cases": cases, "total": count}
         if count > page * limit:
             response["nextPage"] = page + 1
 
diff --git a/data-serving/reusable-data-service/reusable_data_service/main.py b/data-serving/reusable-data-service/reusable_data_service/main.py
index 6764c10bb..9baa14e69 100644
--- a/data-serving/reusable-data-service/reusable_data_service/main.py
+++ b/data-serving/reusable-data-service/reusable_data_service/main.py
@@ -18,8 +18,8 @@ def get_case(id):
 
 @app.route("/api/cases")
 def list_cases():
-    page = request.args.get('page', type=int)
-    limit = request.args.get('limit', type=int)
+    page = request.args.get("page", type=int)
+    limit = request.args.get("limit", type=int)
     return case_controller.list_cases(page=page, limit=limit)
 
 
diff --git a/data-serving/reusable-data-service/reusable_data_service/stores/mongo_store.py b/data-serving/reusable-data-service/reusable_data_service/stores/mongo_store.py
index 8e8838c56..cbef1c404 100644
--- a/data-serving/reusable-data-service/reusable_data_service/stores/mongo_store.py
+++ b/data-serving/reusable-data-service/reusable_data_service/stores/mongo_store.py
@@ -38,7 +38,9 @@ def case_by_id(self, id: str):
             return None
 
     def fetch_cases(self, page: int, limit: int):
-        cases = self.get_case_collection().find({}, skip=(page - 1) * limit, limit = limit)
+        cases = self.get_case_collection().find(
+            {}, skip=(page - 1) * limit, limit=limit
+        )
         return [Case.from_json(dumps(c)) for c in cases]
 
     def count_cases(self) -> int:
diff --git a/data-serving/reusable-data-service/tests/test_case_controller.py b/data-serving/reusable-data-service/tests/test_case_controller.py
index e5ee59f65..21afc4b3f 100644
--- a/data-serving/reusable-data-service/tests/test_case_controller.py
+++ b/data-serving/reusable-data-service/tests/test_case_controller.py
@@ -16,11 +16,12 @@ def put_case(self, id: str, case: Case):
         self.cases[id] = case
 
     def fetch_cases(self, page: int, limit: int):
-        return list(self.cases.values())[(page - 1) * limit: page * limit]
+        return list(self.cases.values())[(page - 1) * limit : page * limit]
 
     def count_cases(self):
         return len(self.cases)
 
+
 @pytest.fixture
 def case_controller():
     with app.app_context():
@@ -71,6 +72,7 @@ def test_list_cases_should_paginate(case_controller):
     assert response.json["nextPage"] == 2
     assert response.json["total"] == 15
 
+
 def test_list_cases_last_page(case_controller):
     with open("./tests/data/case.minimal.json", "r") as minimal_file:
         case = Case.from_json(minimal_file.read())
@@ -82,6 +84,7 @@ def test_list_cases_last_page(case_controller):
     assert response.json["total"] == 15
     assert "nextPage" not in response.json
 
+
 def test_list_cases_nonexistent_page(case_controller):
     with open("./tests/data/case.minimal.json", "r") as minimal_file:
         case = Case.from_json(minimal_file.read())
diff --git a/data-serving/reusable-data-service/tests/test_case_end_to_end.py b/data-serving/reusable-data-service/tests/test_case_end_to_end.py
index b38c995fb..072d2daa8 100644
--- a/data-serving/reusable-data-service/tests/test_case_end_to_end.py
+++ b/data-serving/reusable-data-service/tests/test_case_end_to_end.py
@@ -58,9 +58,12 @@ def test_list_cases_when_none_present_is_empty_list(client_with_patched_mongo):
     assert response.status_code == 200
     assert response.json["cases"] == []
 
+
 def test_list_cases_with_pagination_query(client_with_patched_mongo):
     db = pymongo.MongoClient("mongodb://localhost:27017/outbreak")
-    db["outbreak"]["cases"].insert_many([{"confirmation_date": datetime(2020, 12, 24)} for i in range(25)])
+    db["outbreak"]["cases"].insert_many(
+        [{"confirmation_date": datetime(2020, 12, 24)} for i in range(25)]
+    )
     response = client_with_patched_mongo.get(f"/api/cases?page=2&limit=10")
     assert response.status_code == 200
     assert len(response.json["cases"]) == 10