diff --git a/city_model_structure/surface.py b/city_model_structure/surface.py
index d0936c5a..6486c762 100644
--- a/city_model_structure/surface.py
+++ b/city_model_structure/surface.py
@@ -21,7 +21,7 @@ class Surface:
     self._swr = swr
     self._remove_last = remove_last
     self._is_projected = is_projected
-    self._geometry = GeometryHelper()
+    self._geometry_helper = GeometryHelper()
     self._polygon = None
     self._ground_polygon = None
     self._area = None
@@ -309,7 +309,7 @@ class Surface:
     """
     if self.type != 'Wall' or surface.type != 'Wall':
       return
-    if self._geometry.is_almost_same_surface(self, surface):
+    if self._geometry_helper.is_almost_same_surface(self, surface):
       intersection_area = self.intersect(surface).area
       self.add_shared(surface, intersection_area)
       surface.add_shared(self, intersection_area)
diff --git a/city_model_structure/thermal_opening.py b/city_model_structure/thermal_opening.py
index 68b986b9..f5ab59a9 100644
--- a/city_model_structure/thermal_opening.py
+++ b/city_model_structure/thermal_opening.py
@@ -156,7 +156,7 @@ class ThermalOpening:
   @property
   def overall_u_value(self):
     """
-    Get thermal opening overall u value
+    Get thermal opening overall u value in W/m2K
     :return: float
     """
     return self._overall_u_value
@@ -164,7 +164,7 @@ class ThermalOpening:
   @overall_u_value.setter
   def overall_u_value(self, value):
     """
-    Get thermal opening overall u value
+    Get thermal opening overall u value in W/m2K
     :param value: float
     :return: None
     """
diff --git a/city_model_structure/thermal_zone.py b/city_model_structure/thermal_zone.py
index 392b82f7..5c3638c9 100644
--- a/city_model_structure/thermal_zone.py
+++ b/city_model_structure/thermal_zone.py
@@ -85,7 +85,7 @@ class ThermalZone:
   @property
   def additional_thermal_bridge_u_value(self):
     """
-    Get thermal zone additional thermal bridge u value
+    Get thermal zone additional thermal bridge u value W/m2K
     :return: float
     """
     return self._additional_thermal_bridge_u_value
@@ -93,7 +93,7 @@ class ThermalZone:
   @additional_thermal_bridge_u_value.setter
   def additional_thermal_bridge_u_value(self, value):
     """
-    Set thermal zone additional thermal bridge u value
+    Set thermal zone additional thermal bridge u value W/m2K
     :param value: float
     :return: None
     """
diff --git a/physics/physics_feeders/us_base_physics_parameters.py b/physics/physics_feeders/us_base_physics_parameters.py
index b52b62b1..7b4a750f 100644
--- a/physics/physics_feeders/us_base_physics_parameters.py
+++ b/physics/physics_feeders/us_base_physics_parameters.py
@@ -35,7 +35,7 @@ class UsBasePhysicsParameters:
       archetype = self._search_archetype(building_type,
                                          UsToLibraryTypes.yoc_to_standard(city_object.year_of_construction),
                                          self._climate_zone)
-      # ToDo:remove this in the future
+      # ToDo: remove this in the future
       # ToDo: Raise WrongArchetype if not all the surface types are defined for the given city_object
       if archetype is None:
         print(building_type, UsToLibraryTypes.yoc_to_standard(city_object.year_of_construction),
diff --git a/tests/test_geometry_factory.py b/tests/test_geometry_factory.py
index a0b7a821..7d763035 100644
--- a/tests/test_geometry_factory.py
+++ b/tests/test_geometry_factory.py
@@ -4,9 +4,9 @@ SPDX - License - Identifier: LGPL - 3.0 - or -later
 Copyright © 2020 Project Author Guille Gutierrez guillermo.gutierrezmorote@concordia.ca
 """
 from unittest import TestCase
+import os
 from pathlib import Path
 from geometry.geometry_factory import GeometryFactory
-import os
 
 
 class TestGeometryFactory(TestCase):
@@ -21,13 +21,9 @@ class TestGeometryFactory(TestCase):
     self._city_gml = None
     self._example_path = (Path(__file__).parent.parent / 'tests_data').resolve()
 
-  def get_citygml(self):
-    """
-    Retrieve the test city gml
-    :return: City
-    """
+  def _get_citygml(self):
     if self._city_gml is None:
-      file_path = (self._example_path / '2050 bp_2buildings.gml').resolve()
+      file_path = (self._example_path / 'buildings.gml').resolve()
       self._city_gml = GeometryFactory('citygml', file_path).city
       self.assertIsNotNone(self._city_gml, 'city is none')
     return self._city_gml
@@ -37,7 +33,7 @@ class TestGeometryFactory(TestCase):
     Test the City parsing
     :return: None
     """
-    city = self.get_citygml()
+    city = self._get_citygml()
     self.assertIsNotNone(city.city_objects, 'city_objects is none')
     for city_object in city.city_objects:
       self.assertIsNotNone(city.city_object(city_object.name), 'city_object return none')
@@ -52,7 +48,7 @@ class TestGeometryFactory(TestCase):
     Test city objects in the city
     :return: None
     """
-    city = self.get_citygml()
+    city = self._get_citygml()
     for city_object in city.city_objects:
       self.assertIsNotNone(city_object.name, 'city_object name is none')
       self.assertIsNotNone(city_object.lod, 'city_object lod is none')
@@ -80,7 +76,7 @@ class TestGeometryFactory(TestCase):
     Test surfaces in city objects
     :return: None
     """
-    city = self.get_citygml()
+    city = self._get_citygml()
     for city_object in city.city_objects:
       for surface in city_object.surfaces:
         self.assertIsNotNone(surface.name, 'surface name is none')
@@ -111,7 +107,7 @@ class TestGeometryFactory(TestCase):
     Test thermal zones in city objects
     :return: None
     """
-    city = self.get_citygml()
+    city = self._get_citygml()
     for city_object in city.city_objects:
       for thermal_zone in city_object.thermal_zones:
         self.assertIsNotNone(thermal_zone.surfaces, 'thermal_zone surfaces is none')
@@ -137,7 +133,7 @@ class TestGeometryFactory(TestCase):
     Test thermal boundaries in thermal zones
     :return: None
     """
-    city = self.get_citygml()
+    city = self._get_citygml()
     for city_object in city.city_objects:
       for thermal_zone in city_object.thermal_zones:
         for thermal_boundary in thermal_zone.bounded:
@@ -167,7 +163,7 @@ class TestGeometryFactory(TestCase):
     Test thermal openings in thermal zones
     :return: None
     """
-    city = self.get_citygml()
+    city = self._get_citygml()
     for city_object in city.city_objects:
       for thermal_zone in city_object.thermal_zones:
         for thermal_boundary in thermal_zone.bounded:
diff --git a/tests/test_physics_factory.py b/tests/test_physics_factory.py
index 355a07a5..cfe848b9 100644
--- a/tests/test_physics_factory.py
+++ b/tests/test_physics_factory.py
@@ -13,26 +13,34 @@ class TestPhysicsFactory(TestCase):
   """
   TestPhysicsFactory TestCase
   """
-  def setup(self) -> None:
+  def setUp(self) -> None:
+    """
+    Configure test environment
+    :return:
+    """
     self._city_gml = None
     self._nyc_with_physics = None
     self._example_path = (Path(__file__).parent.parent / 'tests_data').resolve()
 
-  def get_citygml(self):
+  def _get_citygml(self):
     if self._city_gml is None:
       file_path = (self._example_path / 'buildings.gml').resolve()
       self._city_gml = GeometryFactory('citygml', file_path).city
       self.assertIsNotNone(self._city_gml, 'city is none')
     return self._city_gml
 
-  def get_city_with_physics(self):
+  def _get_city_with_physics(self):
     if self._nyc_with_physics is None:
-      self._nyc_with_physics = self.get_citygml()
+      self._nyc_with_physics = self._get_citygml()
       PhysicsFactory('us_new_york_city', self._nyc_with_physics, base_path=self._example_path)
     return self._nyc_with_physics
 
   def test_city_with_physics(self):
-    city = self.get_city_with_physics()
+    """
+    Enrich the city with the physic information and verify ot
+    :return: None
+    """
+    city = self._get_city_with_physics()
     for city_object in city.city_objects:
       self.assertIsNotNone(city_object.average_storey_height, 'average_storey_height is none')
       self.assertIsNotNone(city_object.storeys_above_ground, 'storeys_above_ground is none')
diff --git a/usage/usage_factory.py b/usage/usage_factory.py
index 7fb0d7af..ae84f8e9 100644
--- a/usage/usage_factory.py
+++ b/usage/usage_factory.py
@@ -8,22 +8,29 @@ from usage.usage_feeders.us_new_york_city_usage_parameters import UsNewYorkCityU
 
 
 class UsageFactory:
+  """
+  UsageFactory class
+  """
   def __init__(self, handler, city):
-    self._handler = handler.lower().replace(' ', '_')
+    self._handler = '_' + handler.lower().replace(' ', '_')
     self._city = city
     self.factory()
 
-  def us_new_york_city(self):
+  def _us_new_york_city(self):
     UsNewYorkCityUsageParameters(self._city)
 
-  def ca(self):
+  def _ca(self):
     raise Exception('Not implemented')
 
-  def de(self):
+  def _de(self):
     DeUsageParameters(self._city)
 
-  def es(self):
+  def _es(self):
     raise Exception('Not implemented')
 
   def factory(self):
+    """
+    Enrich the city with the usage information
+    :return: None
+    """
     getattr(self, self._handler, lambda: None)()
diff --git a/usage/usage_feeders/de_usage_parameters.py b/usage/usage_feeders/de_usage_parameters.py
index 48ebd174..7d0fae39 100644
--- a/usage/usage_feeders/de_usage_parameters.py
+++ b/usage/usage_feeders/de_usage_parameters.py
@@ -3,12 +3,15 @@ DeUsageParameters model the usage properties for a German building
 SPDX - License - Identifier: LGPL - 3.0 - or -later
 Copyright © 2020 Project Author Guille Gutierrez guillermo.gutierrezmorote@concordia.ca
 """
-import xmltodict
 from pathlib import Path
+import xmltodict
 from usage.usage_feeders.helpers.us_function_to_usage import UsFunctionToUsage
 
 
 class DeUsageParameters:
+  """
+  DeUsageParameters
+  """
   def __init__(self, city_objects):
     self._city_objects = city_objects
 
@@ -17,4 +20,4 @@ class DeUsageParameters:
     with open(path) as xml:
       self._library = xmltodict.parse(xml.read())
     for city_object in city_objects:
-       UsFunctionToUsage.function_to_usage(city_object.function)
+      UsFunctionToUsage.usage(city_object.function)
diff --git a/usage/usage_feeders/us_base_usage_parameters.py b/usage/usage_feeders/us_base_usage_parameters.py
index df65e610..9444444b 100644
--- a/usage/usage_feeders/us_base_usage_parameters.py
+++ b/usage/usage_feeders/us_base_usage_parameters.py
@@ -3,13 +3,16 @@ UsBaseUsageParameters base class to model the usage properties for a building in
 SPDX - License - Identifier: LGPL - 3.0 - or -later
 Copyright © 2020 Project Author Guille Gutierrez guillermo.gutierrezmorote@concordia.ca
 """
-import xmltodict
 from pathlib import Path
+import xmltodict
 from city_model_structure.usage_zone import UsageZone
 from city_model_structure.internal_gains import InternalGains
 
 
 class UsBaseUsageParameters:
+  """
+  UsBaseUsageParameters class
+  """
   def __init__(self, city, function_to_usage):
     self._city = city
     # ToDo: this is using the german library as a temporary approach, need to use/define a library for US
@@ -17,7 +20,7 @@ class UsBaseUsageParameters:
     with open(path) as xml:
       self._library = xmltodict.parse(xml.read(), force_list='zoneUsageVariant')
     for city_object in self._city.city_objects:
-      #ToDo: Right now is just one usage zone but will be multiple in the future
+      # ToDo: Right now is just one usage zone but will be multiple in the future
       usage_zone = UsageZone()
       usage_zone.usage = function_to_usage(city_object.function)
       for zone_usage_type in self._library['buildingUsageLibrary']['zoneUsageType']:
@@ -31,14 +34,12 @@ class UsBaseUsageParameters:
                 city_object.usage_zone = [usage_zone]
                 break
           continue
-        else:
-          city_object.usage_zones = [UsBaseUsageParameters._parse_zone_usage_type(zone_usage_type, usage_zone)]
-          break
+        city_object.usage_zones = [UsBaseUsageParameters._parse_zone_usage_type(zone_usage_type, usage_zone)]
+        break
       if city_object.usage_zones is None:
         print(city_object.function)
         raise Exception('Usage not found for building function')
 
-
   @staticmethod
   def _parse_zone_usage_type(zone_usage_type, usage_zone):
     usage_zone.hours_day = zone_usage_type['occupancy']['usageHoursPerDay']
diff --git a/usage/usage_feeders/us_new_york_city_usage_parameters.py b/usage/usage_feeders/us_new_york_city_usage_parameters.py
index d3a5a516..4d71a634 100644
--- a/usage/usage_feeders/us_new_york_city_usage_parameters.py
+++ b/usage/usage_feeders/us_new_york_city_usage_parameters.py
@@ -8,6 +8,9 @@ from usage.usage_feeders.helpers.us_pluto_to_usage import UsPlutoToUsage as Pu
 
 
 class UsNewYorkCityUsageParameters(UsBaseUsageParameters):
+  """
+  UsNewYorkCityUsageParameters class
+  """
   def __init__(self, city):
     self._city = city
     super().__init__(self._city, Pu.usage)
diff --git a/usage/usage_feeders/us_usage_parameters.py b/usage/usage_feeders/us_usage_parameters.py
index b24085d6..33fa8e7b 100644
--- a/usage/usage_feeders/us_usage_parameters.py
+++ b/usage/usage_feeders/us_usage_parameters.py
@@ -8,5 +8,8 @@ from usage.usage_feeders.helpers.us_function_to_usage import UsFunctionToUsage
 
 
 class UsUsageParameters(UsBaseUsageParameters):
+  """
+  UsUsageParameters class
+  """
   def __init__(self, city):
     super().__init__(city, UsFunctionToUsage.usage)