diff --git a/.github/workflows/etl.yml b/.github/workflows/etl.yml
index 9b8208d4..0d56a433 100644
--- a/.github/workflows/etl.yml
+++ b/.github/workflows/etl.yml
@@ -16,7 +16,7 @@ jobs:
         python -m pip install -r requirements.txt
     - name: Run Flake8
       run: |
-        ls etl/*py | grep -v 'join_building_data' | xargs flake8
+        ls etl/*py | grep -v 'join_building_data' | xargs flake8 --exclude etl/__init__.py
     - name: Run tests
       run: |
         python -m pytest
\ No newline at end of file
diff --git a/etl/filter_mastermap.py b/etl/filter_mastermap.py
index 2167a53c..3315a6ca 100644
--- a/etl/filter_mastermap.py
+++ b/etl/filter_mastermap.py
@@ -4,13 +4,13 @@
 """
 import csv
 import glob
-import json
 import os
 import sys
 
 
 csv.field_size_limit(sys.maxsize)
 
+
 def main(mastermap_path):
     mm_paths = sorted(glob.glob(os.path.join(mastermap_path, "*.gml.csv")))
     for mm_path in mm_paths:
@@ -19,7 +19,8 @@ def main(mastermap_path):
 
 
 def filter_mastermap(mm_path):
-    output_path =  "{}.filtered.csv".format(str(mm_path).replace(".gml.csv", ""))
+    output_path = "{}.filtered.csv"
+    output_path.format(str(mm_path).replace(".gml.csv", ""))
     output_fieldnames = ('WKT', 'fid', 'descriptiveGroup')
     # Open the input csv with all polygons, buildings and others
     with open(mm_path, 'r') as fh:
@@ -32,7 +33,8 @@ def filter_mastermap(mm_path):
                 try:
                     if 'Building' in line['descriptiveGroup']:
                         w.writerow(line)
-                except TypeError:  # when descriptiveGroup is missing, ignore this Polygon
+                # when descriptiveGroup is missing, ignore this Polygon
+                except TypeError:
                     pass
 
 
diff --git a/etl/get_test_polygons.py b/etl/get_test_polygons.py
index 6b1b34e3..388b9872 100644
--- a/etl/get_test_polygons.py
+++ b/etl/get_test_polygons.py
@@ -25,11 +25,12 @@ gdf = osmnx.footprints_from_point(point=point, dist=dist)
 
 # preview image
 gdf_proj = osmnx.projection.project_gdf(gdf, to_crs={'init': 'epsg:3857'})
-gdf_proj = gdf_proj[gdf_proj.geometry.apply(lambda g: g.geom_type != 'MultiPolygon')]
+gdf_proj = gdf_proj[gdf_proj.geometry.apply(lambda g: g.geom_type != 'MultiPolygon')]  # noqa
 
-fig, ax = osmnx.plot_footprints(gdf_proj, bgcolor='#333333', color='w', figsize=(4,4),
-                               save=True, show=False, close=True,
-                               filename='test_buildings_preview', dpi=600)
+fig, ax = osmnx.plot_footprints(gdf_proj, bgcolor='#333333',
+                                color='w', figsize=(4, 4),
+                                save=True, show=False, close=True,
+                                filename='test_buildings_preview', dpi=600)
 
 # save
 test_dir = os.path.dirname(__file__)
@@ -50,7 +51,13 @@ gdf_to_save.rename(
 # convert to CSV
 test_data_csv = str(os.path.join(test_dir, 'test_buildings.3857.csv'))
 subprocess.run(["rm", test_data_csv])
-subprocess.run(["ogr2ogr", "-f", "CSV", test_data_csv, test_data_geojson, "-lco", "GEOMETRY=AS_WKT"])
+subprocess.run(
+                ["ogr2ogr", "-f", "CSV", test_data_csv,
+                 test_data_geojson, "-lco", "GEOMETRY=AS_WKT"]
+)
 
 # add SRID for ease of loading to PostgreSQL
-subprocess.run(["sed", "-i", "s/^\"POLYGON/\"SRID=3857;POLYGON/", test_data_csv])
+subprocess.run(
+                ["sed", "-i", "s/^\"POLYGON/\"SRID=3857;POLYGON/",
+                 test_data_csv]
+)