diff --git a/tests/test_wtw.py b/tests/test_wtw.py
index c4ea92c0..f1d25d81 100644
--- a/tests/test_wtw.py
+++ b/tests/test_wtw.py
@@ -127,27 +127,29 @@ def test_wwtw_overrides(self):
         self.assertEqual(wwtw.process_parameters["phosphate"]["constant"], 0.01)
         self.assertEqual(wwtw.process_parameters["volume"]["constant"], vol)
         self.assertEqual(wwtw.stormwater_storage_capacity, 100)
-    
+
     def test_fwtw_overrides(self):
-        fwtw = FWTW(name='')
-        vol = fwtw.process_parameters['volume']['constant']
-        fwtw.apply_overrides({'treatment_throughput_capacity' : 20,
-                              'process_parameters' : {'phosphate' : 
-                                                      {'constant' : 0.02}},
-                              'service_reservoir_storage_capacity': 100,
-                              'service_reservoir_storage_area': 34.7,
-                              'service_reservoir_storage_elevation': 68.2
-                              })
+        fwtw = FWTW(name="")
+        vol = fwtw.process_parameters["volume"]["constant"]
+        fwtw.apply_overrides(
+            {
+                "treatment_throughput_capacity": 20,
+                "process_parameters": {"phosphate": {"constant": 0.02}},
+                "service_reservoir_storage_capacity": 100,
+                "service_reservoir_storage_area": 34.7,
+                "service_reservoir_storage_elevation": 68.2,
+            }
+        )
         self.assertEqual(fwtw.treatment_throughput_capacity, 20)
-        self.assertEqual(fwtw.process_parameters['phosphate']['constant'], 0.02)
-        self.assertEqual(fwtw.process_parameters['volume']['constant'], vol)
+        self.assertEqual(fwtw.process_parameters["phosphate"]["constant"], 0.02)
+        self.assertEqual(fwtw.process_parameters["volume"]["constant"], vol)
         self.assertEqual(fwtw.service_reservoir_storage_capacity, 100)
         self.assertEqual(fwtw.service_reservoir_tank.capacity, 100)
         self.assertEqual(fwtw.service_reservoir_storage_area, 34.7)
         self.assertEqual(fwtw.service_reservoir_tank.area, 34.7)
         self.assertEqual(fwtw.service_reservoir_storage_elevation, 68.2)
         self.assertEqual(fwtw.service_reservoir_tank.datum, 68.2)
-        self.assertEqual(fwtw.process_parameters['nitrate']['constant'], 0.01)
+        self.assertEqual(fwtw.process_parameters["nitrate"]["constant"], 0.01)
 
 
 if __name__ == "__main__":
diff --git a/wsimod/nodes/wtw.py b/wsimod/nodes/wtw.py
index d593db8b..002313dc 100644
--- a/wsimod/nodes/wtw.py
+++ b/wsimod/nodes/wtw.py
@@ -547,26 +547,28 @@ def apply_overrides(self, overrides=Dict[str, Any]):
 
         Enables a user to override any parameter of the service reservoir tank, and
         then calls any overrides in WTW.
-        
+
         Args:
             overrides (Dict[str, Any]): Dict describing which parameters should
                 be overridden (keys) and new values (values). Defaults to {}.
         """
         self.service_reservoir_storage_capacity = overrides.pop(
-            "service_reservoir_storage_capacity", 
-            self.service_reservoir_storage_capacity)
+            "service_reservoir_storage_capacity",
+            self.service_reservoir_storage_capacity,
+        )
         self.service_reservoir_storage_area = overrides.pop(
-            "service_reservoir_storage_area", 
-            self.service_reservoir_storage_area)
+            "service_reservoir_storage_area", self.service_reservoir_storage_area
+        )
         self.service_reservoir_storage_elevation = overrides.pop(
-            "service_reservoir_storage_elevation", 
-            self.service_reservoir_storage_elevation)
+            "service_reservoir_storage_elevation",
+            self.service_reservoir_storage_elevation,
+        )
 
         self.service_reservoir_tank.capacity = self.service_reservoir_storage_capacity
         self.service_reservoir_tank.area = self.service_reservoir_storage_area
         self.service_reservoir_tank.datum = self.service_reservoir_storage_elevation
         super().apply_overrides(overrides)
-    
+
     def treat_water(self):
         """Pulls water, aiming to fill service reservoirs, calls WTW
         treat_current_input, avoids deficit, sends liquor and solids to sewers."""