diff --git a/datatypes/epc/domain/dwelling.py b/datatypes/epc/domain/dwelling.py
index b60cec35..d7faff50 100644
--- a/datatypes/epc/domain/dwelling.py
+++ b/datatypes/epc/domain/dwelling.py
@@ -1,12 +1,12 @@
-from dataclasses import dataclass, field
+from dataclasses import dataclass
 from typing import List, Optional
 
 
 @dataclass
 class PropertyDetails:
-    property_type: str          # e.g. "House", "Flat"
-    built_form: str             # e.g. "Mid-terrace", "Detached"
-    tenure: str                 # e.g. "Owner-occupied", "Rented Social"
+    property_type: str  # e.g. "House", "Flat"
+    built_form: str  # e.g. "Mid-terrace", "Detached"
+    tenure: str  # e.g. "Owner-occupied", "Rented Social"
     number_of_storeys: int
     construction_age_band: Optional[str] = None  # e.g. "1950-1966", "I: 1996 - 2002"
     transaction_type: Optional[str] = None
@@ -19,6 +19,7 @@ class PropertyDetails:
 @dataclass
 class FloorDimensions:
     """Floor area and geometry for one storey of one building part."""
+
     total_floor_area_m2: float
     height_m: float
     heat_loss_perimeter_m: Optional[float] = None
@@ -27,29 +28,29 @@ class FloorDimensions:
 
 @dataclass
 class WallDetails:
-    construction_type: str      # e.g. "Cavity", "Solid masonry"
-    insulation_type: str        # e.g. "As built", "Filled cavity", "External"
+    construction_type: str  # e.g. "Cavity", "Solid masonry"
+    insulation_type: str  # e.g. "As built", "Filled cavity", "External"
     thickness_mm: Optional[int] = None
     party_wall_construction_type: Optional[str] = None
 
 
 @dataclass
 class RoofDetails:
-    construction_type: str      # e.g. "Pitched, access to loft", "Flat"
-    insulation_at: Optional[str] = None         # e.g. "Joists", "Rafters"
+    construction_type: str  # e.g. "Pitched, access to loft", "Flat"
+    insulation_at: Optional[str] = None  # e.g. "Joists", "Rafters"
     insulation_thickness_mm: Optional[int] = None
     has_rooms_in_roof: bool = False
 
 
 @dataclass
 class FloorDetails:
-    construction_type: str      # e.g. "Solid", "Suspended timber"
-    insulation_type: Optional[str] = None       # e.g. "As built", "Insulated"
+    construction_type: str  # e.g. "Solid", "Suspended timber"
+    insulation_type: Optional[str] = None  # e.g. "As built", "Insulated"
 
 
 @dataclass
 class WindowDetails:
-    glazing_type: str           # e.g. "Double glazing", "Triple glazing"
+    glazing_type: str  # e.g. "Double glazing", "Triple glazing"
     orientation: Optional[str] = None
     frame_type: Optional[str] = None
     glazing_gap: Optional[str] = None
@@ -60,21 +61,21 @@ class WindowDetails:
 
 @dataclass
 class MainHeatingSystem:
-    fuel: str                   # e.g. "Mains gas", "Oil", "Electricity"
-    system_type: str            # e.g. "Boiler with radiators or underfloor heating"
-    boiler_type: Optional[str] = None           # e.g. "Regular", "Combi"
+    fuel: str  # e.g. "Mains gas", "Oil", "Electricity"
+    system_type: str  # e.g. "Boiler with radiators or underfloor heating"
+    boiler_type: Optional[str] = None  # e.g. "Regular", "Combi"
     manufacturer: Optional[str] = None
     model: Optional[str] = None
     condensing: Optional[bool] = None
     controls: Optional[str] = None
     flue_gas_heat_recovery: bool = False
     weather_compensator: bool = False
-    emitter: Optional[str] = None              # e.g. "Radiators", "Underfloor"
+    emitter: Optional[str] = None  # e.g. "Radiators", "Underfloor"
 
 
 @dataclass
 class HotWaterSystem:
-    source: str                 # e.g. "From main heating 1", "Immersion heater"
+    source: str  # e.g. "From main heating 1", "Immersion heater"
     cylinder_size: Optional[str] = None
     insulation_type: Optional[str] = None
     insulation_thickness_mm: Optional[int] = None
@@ -83,12 +84,12 @@ class HotWaterSystem:
 
 @dataclass
 class SecondaryHeatingSystem:
-    fuel: str                   # e.g. "Wood logs", "Electricity"
+    fuel: str  # e.g. "Wood logs", "Electricity"
 
 
 @dataclass
 class VentilationDetails:
-    ventilation_type: str       # e.g. "Natural", "Mechanical Extract - Decentralised"
+    ventilation_type: str  # e.g. "Natural", "Mechanical Extract - Decentralised"
     number_of_open_flues: int = 0
     number_of_closed_flues: int = 0
     number_of_boiler_flues: int = 0